Request For Quotation. Eigenschaften Sicherheit Verwendungswort Produktionsfirma EPA chemische Informationen Asbestos Beschreibung Asbestos is a fibrous silicate of magnesium and calcium. Asbestine pulp as a certain variety of the material mined at the foot of the Adirondack mountains is known to the trade , although it is sold in the dry powdered form, belongs really to the soapstone or talc variety. But it is not as unctuous as either of those, has a harder texture, and is of whiter color than either soapstone or talc.
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US3864181A - Polymer foam compositions - Google PatentsVIDEO ON THE TOPIC: X11 wendy press machine special for brake pads mold change of hot forming friction material
Related U. Application Data Division of Ser. The compositions comprise a dispersion of microspheres in a solution of the polymer in a solvent.
The compositions are applied to substrate, dried, and heated to expand the microspheres, thus formong a foamed polymer. The present invention relates to a foamable polymer coating composition, and more particularly to polymer coating compositions which can be foamed and expanded at any convenient point during manufacture or use.
Still more particularly, it relates to polymer coating solutions which can be employed in any conventional coating process, such as spraying, brushing, printing, dip coating and the like, and can be subsequently foamed and expanded in situ, either in selected areas or in toto. The present invention also relates to a method of forming foamed and expanded polymer coatings by conventional coating technique utilizing liquid polymeric coating solutions wherein the coating is foamed and expanded in situ at any convenient point after the coating is applied.
The invention also relates to coatings of foamed polymeric materials formed in accordance with the process composition of the present invention. Foamed polymer compositions are widely employed in a number of contexts for their ability to absorb mechanical, electrical, thermal and acoustical energy, their low density, their particular surface characteristics of texture and non-skid and non-abrasive surfaces and for their unusual appearance.
For example, polymer foams are frequently applied to metals, such as metal furniture, automobile doors and other panels, metal roofs, heating and cooling ducts, office machines, containers and the like, to reduce noise. Light-weight encapsulating formulations for potting electrical components and the like often rely upon electrically resistant polymer foams. The absorption of mechanical shocks and the like is an important area for the usage of foamed polymers in packaging offragile materials such as for example, eggs, electrical components, light bulbs, optical instruments, jewelry, fruits and vegetables, glassware, ceramics, and many other materials.
The particular surface characteristics of foamed polymers have been utilized in non-skid coatings for carpets, rugs, bathtub mats, flooring, coat hangers, handles for tools and athletic equipment such as baseball bats and tennis rackets and the like.
The low density of foamed plastics has been utilized for flotation for boats, floating piers and docks, flotation apparel and life jackets, and as low density fillers for construction materials such as bricks, concrete blocks and structures and the like. The particular features of the appearance of foamed polymers have been employed for decorative effects, such as soft three-dimensional raised surfaces.
Examples are Landau tops of automobiles, Christmas ornaments, synthetic leather materials and the like. It is clear that the foamed polymer compositions are of substantial importance and have found wide usage in industry in many and diverse contexts. There are, however, serious limitations on the employment of foamed polymers and not all areas where such materials would be desirable have been developed.
In addition, the technology of foamed polymer compositions is complex, expensive and very time consuming. A considerable amount of manipulation is required, frequently also requiring substantial amounts of hand labor. Normally foamed polymer materials are available as solid, foamed sheets or blocks often laminated with an adhesive to a backing such as paper board, metal sheets or metal foils. The sheets or other form of foamed polymeric material require extensive cutting and shaping to meet the requirements of usage, and then must be fastened in place by the use oflaminating adhesives or the like.
Much time, fabricating space, specialized equipment and labor is required for such operations and except in the highest volume operations, substantial hand labor is required. In addition, much wastage results from shaping operations. The employment of adhesives to laminate foamed materials to a substrate not only requires additional expensive materials and labor, but also presents problems of quality control and product uniformity.
The bulk of foamed polymers require substantial space for storage and shipping facilities as well. Many attempts have been made to improve the state of the art but these have met with limited success at best.
For example, it has been proposed to polymerize in situ from prepolymers" containing blowing agents. Such procedures have been employed in some contexts but generally require extensive investments in equipment and specialized labor and are subject to substantial variations in product quality. Such procedures are also relatively slow and are not generally applicable to all needs, and are basically limited to the preparation of substantially large and monolithic forms such as cushions, low density flotation and the like.
Even there, such foaming techniques require molds and the process is not generally suitable for forming coatings. Another attempt to improve the state of the art entails the formation of a laminated sheet of a foamable polymer composition layer and an adhesive layer with strippable facing layers over both the foamable polymer and the adhesive.
The composite is cut to the desired shape and laminated to a substrate by removing the facing layer from the adhesive layer, then pressing the shaped composite into place. Foaming is accomplished by heating, which may also serve to bind the adhesive to the substrate. The foamable polymer which enables the technique is a thermoplastic material in the form of small expanded particles which encapsulate a thermally activated blowing agent dispersed in a minor amount.
Such materials are known to the art and are disclosed for example, in Belgian Pat. The techniques employing the socalled microspheres have a number of advantages over more conventional technology since the bulk of the materials is substantially less prior to foaming and the provision of a preformed laminatev of the adhesive component greatly facilitates operations. However, the technique still requires substantial manipulation with consequent high cost for labor and equipment.
In addition, the materials are more expensive and limitations upon the areas of utilization of foamed polymers is not changed. Another employment of the microspheres has been to incorporate them in aqueous emulsion or latex type coating compositions which can be employed as conventional coating compositions.
After the coating has dried, the microspheres can be expanded by the application of heat, thus also expanding the coating. It has long been a desire of those skilled in the art to simplify foamed polymer technology and to provide reliable and economical means for applying foamed polymer coatings and adhesives to substrate from solutions. It is a further object of the present invention to provide foamed polymer coatings and adhesives by such techniques. These and still other objects are realized by the present invention, of which the following is a full disclosure.
It has now been found that substantially any thermoplastic coating or adhesive polymer can be formulated into a liquid coating or adhesive solution, coated on a substrate, and subsequently foamed in situ, by incorporating into said liquid coating solution about 0.
The temperatures of the foaming step will ordinarily be in the range of from about to F. The temperature and length ofheating can be manipulated to attain either an open cell or a closed cell foam as desired.
The density of the coating can be reduced by any desired degree to as little as 0. The volume of the coating is increased in comparable fashion up to as much as volumes for an open cell and volumes for a closed cell.
Substantially any natural or synthetic thermoplastic polymer can be employed in the process of the present invention, including also thermally cross-linkable or thermosettable polymers which react at foaming temperatures to a cross-linked or thermo-set condition. As examples of foamable thermoplastic coating polymers, there can be mentioned polymers of ethylenically unsaturated monomers, such as polyethylene, polypropylene, polybutenes, polystyrene, poly a-methyl styrene , polyvinyl chloride, polyvinyl acetate, polymethyl methacrylate, polyethyl acrylate, polyacrylonitrile and the like; copolymers of ethylenically unsaturated monomers such as copolymers of ethylene and propylene, ethylene and styrene, and polyvinyl acetate, styrene and maleic anhydride.
In addition, such polymers can be formulated with curing or cross-linking agents activated at foaming temperatures to provide foamed, cured or cross-linked variations of the foregoing types of polymers. Such curing and cross-linking techniques are well known in the art and include for example, the use of free radical generators such as peroxides and the like, compounds reactive with double bonds such as sulfur and the like, or compounds reactive with pendant groups on the polymer chains such as the the reaction of polyisocyanates with pendanthydroxyl groups, the reaction of polyols with pendant isocyanate groups and the like.
In addition, the foamable polymer can also be a thermoset material stabilized at a preliminary stage of polymerization and still deformable at elevated temperatures. Examples include epoxy polymers, phenol-formaldehyes, ureaformaldehydes, melamine-formaldehydes and the like,. The compositions of the present invention are formed by providing the coating or adhesive polymer and microspheres in a liquid solvent for the polymer together with other conventional ingredients of coating compositions.
The liquid medium is a solvent for the polymer but must be a non-solvent, or at least have limited solvent activity for the microspheres. The microspheres are readily wetted by organic solvents and are of particle sizes which make them readily and stably dispersible.
In circumstances where it is necessary to use a solvent having a more substantial solvent activity for the microspheres, by virtue of the character of the coating polymer or the contemplated utilization of the coating solution, it is possible to treat the microspheres to reduce or eliminate their solubility in the solvent required.
A number of techniques are available. Among the simplest of these is a technique useful when the solvent of choice has a definite, but not great, solvent activity. The microspheres can be coated with a material which preferentially wets the surface of the microspheres but which is a non-solvent. Butyl alcohols, particularly n-butyl alcohol, are often useful for such a purpose.
In more extreme circumstances, such as when a strong solvent for the material of the microspheres is employed or when long shelf life coating solution is required, more extensive treatments are required. In such contexts it has been found useful to coat the microspheres with a diverse polymer which is not soluble in the contemplated solvent and which will readily wet when in solution and coat the microspheres.
Among the polymers which can be effectively employed in such a context are for example, acrylics, polyesters, alkyds, polyamides, cross-linked epoxies, ureaformaldehydes and phenol formaldehydes.
Accordingly, by virtue of such techniques, there are substantially no restrictions upon the solvents which can be employed in conjunction with the microspheres. For substantially any solvent the microspheres can be used alone, preferentially wetted as with butyl alcohol, or coated with a polymer insoluble in the solvent. Among the solvents which can be employed without resort to preferential wetting or coating of microspheres there can be mentioned for example, water, alkanes, preferably straight chain alkanes, aliphatic alcohols, preferably straight chain aliphatic alcohols, and aromatics, preferably those with short-chain aliphatic substituents on the ring, e.
The microspheres employed in the present invention are hollow thermoplastic particles and are of relatively small size, usually less than about to microns in diameter and can be as small as about 0. Preferably micron diameters of from about 3 to 50, and more preferably about 5 to 20, are employed. The microspheres have a generally spherical shape and define a generally concentric spherical cavity inside containing about 5 to 50 weight percent of a volatile blowing agent, insoluble or at most only slightly soluble in the thermoplastic material of the microsphere.
Microspheres of such character can be prepared with bulk densities ranging from about 50 to 90 pounds per cubic foot. The thermoplastic of the microspheres can be generally any thermoplastic polymer but if the formation of a solution coating composition is contemplated, the thermoplastic of the microspheres should be different from the foamable coating polymer and not soluble in the solvent.
Hence, in varying contexts, the thermoplastic of the microspheres can be chosen from among the same polymers disclosed as suitable for the foamable coating polymer.
The microspheres can be conveniently prepared by the techniques referred to as a limited coalescence polymerization technique. A typical preparation of such particles is as follows:. A polymerization reactor equipped with an agitator is charged with parts by weight of deionized water and parts by weight of a 30 weight percent colloidal silica dispersion in water. The colloidal silica dispersion is 30 weight percent solids and is available under the tradename ofLudox HS.
To this mixture is added 2. One part by weight of a solution containing 2. The pH of the aqueous solution is adjusted to 4 with hydrochloric acid. Vinylidene chloride is utilized as the monomer. An oil phase mixture is prepared by utilizing parts by weight of vinylidene chloride and parts by weight neopentane The oil phase mixture is added to the water phase with violent agitation supplied by a blade rotating at a speed of about 10, rpm.
The reactor is immediately sealed and portion sampled to determine the particle size. The droplets appear to have diameters of from 2 to about 10 microns. After the initial disperson, the reaction mixtures are maintained at a temperature of about 80C. At the end of this period, the temperature is lowered and the reaction mixture is found to have the appearance of a white, milky liquid similar to a chalk-white milk.
A portion of the mixture is filtered to remove the particles and the particles or beads are subsequently dried for about I hour in an air oven at the temperature of about 30C.
A portion of the dried spherical particles are heated in an air oven at a temperature of C. Upon heating, the particles show a marked increase in volume.
Microscopic examination of the particles prior to foaming indicates particles having diameters of from about 2 to about 10 microns and having disposed therein a distinct spherical zone which appears to contain liquid and a small vapor space. The particles which are heated are examined microscopically and are found to have diameters of from about 2 to 5 times the diameter of the original particles and to have a relatively thin, transparent wall and a gaseous center, i.
Preferred polymers for preparation of the microspheres are for example, polyvinylidene chloride, a copolymer of vinylidene chloride and acrylonitrile in weight ratios of about ] to about , copolymers of acrylonitrile and methyl acrylate in weight ratios of about 10 to , and copolymers of methacrylonitrile and methyl acrylate in weight ratios of about to While these materials and proportions are preferred, it is not intended that the invention be limited thereto.
The preference is grounded principally in convenience and not in any substantive considerations. By utilizing the technique of limited coalescence, a wide variety of expandable thermoplastic microcellular particles can be prepared.
Such materials are now familiar to the art and are commercially available as has been mentioned above, and for convenience are referred to generically hereinafter as microspheres.
Asbestos mining existed more than 4, years ago, but large-scale mining began at the end of the 19th century, when manufacturers and builders began using asbestos for its desirable physical properties:  sound absorption , average tensile strength , resistance to fire , heat, electricity, and affordability. It was used in such applications as electrical insulation for hotplate wiring and in building insulation. When asbestos is used for its resistance to fire or heat, the fibers are often mixed with cement or woven into fabric or mats. These desirable properties made asbestos very widely used.
Asbestos - Wikipedia, The Free Encyclopedia
Request For Quotation. EPA Asbestos Asbestine pulp as a certain variety of the material mined at the foot of the Adirondack mountains is known to the trade , although it is sold in the dry powdered form, belongs really to the soapstone or talc variety. But it is not as unctuous as either of those, has a harder texture, and is of whiter color than either soapstone or talc. Insoluble in water. Asbestos is a generic term that applies to a number of naturally occurring, hydrated mineral silicates incombustible in air and separable into filaments. The most widely used in industry in the United States is chrysotile, a fibrous form of serpentine.
In this case, the required characteristics include packaging material slit suitability and gas barrier properties. In order to satisfy these various characteristics, various packaging materials have been conventionally proposed. Cross-laminate films have been proposed. The packaging material laminated stacked above is proposed. There was a problem. Moreover, it was difficult for aluminum foil to remove the rolling oil used at the time of rolling completely by annealing, and it deteriorated photographic properties. It is an object of the present invention to provide a photosensitive material packaging material, a method for producing the same, and a photosensitive material package using the same.SEE VIDEO BY TOPIC: FIRESTONE WORLD BESTOS COMPANY ASBESTOS BRAKE PADS PROMO FILM "STOPPING POWER" 1950s TRUCKS 65344
NCBI Bookshelf. Carbon Black, Titanium Dioxide, and Talc. The mineralogy of airborne particles in talc mines is restricted by that of the deposit and associated rocks. Therefore, mines and mills provide an opportunity to characterize exposure to one specific source of talc mineralogically. In contrast, the mineralogy of talc in an industrial setting where talc products are used may be difficult to characterize, because many different sources of talc are available for almost every application. Industrial talcs are quite variable in their talc content and in the identity and proportion of other minerals that they contain. In addition, talc is part of a complex mixture of materials in user industries. Talc particles are normally plate-like. When viewed under the microscope in bulk samples or on air filters, they may appear to be fibres and have been identified as such. Asbestiform talc fibres are very long and thin and occur in parallel bundles that are easily separated from each other by hand pressure.
All are composed of long and thin fibrous crystals , each fiber being composed of many microscopic 'fibrils' that can be released into the atmosphere by abrasion and other processes. Asbestos is an excellent electrical insulator and is highly resistant to heat, so for many years it was used as a building material. Inhalation of asbestos fibres can lead to various serious lung conditions, including asbestosis and cancer. Archaeological studies have found evidence of asbestos being used as far back as the Stone Age to strengthen ceramic pots,  but large-scale mining began at the end of the 19th century when manufacturers and builders began using asbestos for its desirable physical properties. Asbestos was widely used during the 20th century until the s when public recognition of the health hazards of asbestos dust led to its outlawing in mainstream construction and fireproofing in most countries. Despite the severity of asbestos-related diseases, the material has been used widely all around the world, and most pres buildings are thought to contain asbestos. It was adopted via the Old French abestos, which in turn got the word from Greek via Latin , but in the original Greek, it actually referred to quicklime. It is said by the Oxford English Dictionary to have been wrongly used by Pliny for asbestos, who popularized the misnomer.
Related U. Application Data Division of Ser. The compositions comprise a dispersion of microspheres in a solution of the polymer in a solvent. The compositions are applied to substrate, dried, and heated to expand the microspheres, thus formong a foamed polymer. The present invention relates to a foamable polymer coating composition, and more particularly to polymer coating compositions which can be foamed and expanded at any convenient point during manufacture or use. Still more particularly, it relates to polymer coating solutions which can be employed in any conventional coating process, such as spraying, brushing, printing, dip coating and the like, and can be subsequently foamed and expanded in situ, either in selected areas or in toto. The present invention also relates to a method of forming foamed and expanded polymer coatings by conventional coating technique utilizing liquid polymeric coating solutions wherein the coating is foamed and expanded in situ at any convenient point after the coating is applied. The invention also relates to coatings of foamed polymeric materials formed in accordance with the process composition of the present invention.
Fibrous asbestos on muscovite. Blue asbestos crocidolite from Wittenoom, Western Australia. The ruler is 1 cm. They all have in common their asbestiform habit, long, thin fibrous crystals. The inhalation of asbestos fibres can cause serious illnesses, including malignant lung cancer , mesothelioma a formerly rare cancer strongly associated with exposure to asbestos , and asbestosis a type of pneumoconiosis. Since January 1, , the European Union has banned all use of asbestos  and extraction, manufacture and processing of asbestos products. For environmental samples, one must normally resort to electron microscopy for positive identification. However, the latter techniques cannot readily identify the smallest, most hazardous, fibers, because they are limited to PM10 particulate size evaluation, which completely ignores ultrafine particles UFPs. Asbestos became increasingly popular among manufacturers and builders in the late 19th century because of its sound absorption, average tensile strength, and its resistance to heat, electrical and chemical damage.
This is a divisional of application Ser. This invention relates to a color masterbatch resin composition for a packaging material for a photographic photosensitive material, production.
Мы не успели вовремя предпринять необходимые действия. И, что уж совсем серьезно, -- человек, который помог вам открыть Лиз, исчез.
Здесь, на круговом пространстве диаметром более трех миль, жила память о том, чем была Земля в те дни, когда пустыня еще не поглотила, как теперь, поверхность планеты, обойдя лишь Диаспар.
Сначала шел широкий пояс луга, затем -- низкорослые деревья, заросли которых становились все гуще и гуще по мере того, как гуляющий углублялся под их кроны.
Ее работы можно было увидеть по всему Диаспару, и по мотивам некоторых из этих композиций были даже созданы мозаики полов в гигантских хореографических залах -- рисунок пола служил своего рода основой для создателей новых танцевальных вариаций. Все эти занятия могли бы показаться бесплодными тому,кто не обладал достаточным интеллектом, чтобы оценить их тонкость. Но в Диаспаре не нашлось бы ни единого человека, который не смог бы понять то, что пытались создать Эристон и Итания, и кем ж двигал бы такой же всепоглощающий интерес.