Патент USA US3095321код для вставки
‘a, 106*‘10 United States Patent 0 an , LAf'llVl | wen 3,095,312 ‘ 1C6 Patented June 25, 1963 2 1 duce a water-insoluble foamed product. This ratio is 3,095,312 POROUS FOAMED SILICATE PRODUCTS Sidney T. Holmes, 1410 Warrington Road, Deer?eld, Ill. No Drawing. Filed Dec. 24, 1959, Ser. Nmw 2 Claims. (Cl. 106-75) This invention deals with the production of inexpen the portion of total Nazo to paraformaldehyde used, which should be less than 3 to l, and preferably less than 2 to 1. It is apparent that, when metals other than so 5 dium are used in the silicate, the ratio ?gures must be adjusted accordingly. At the same time, the total amount sive, essentially inorganic, foamed products formed by expanding a mixture__i_nt9_ nah liar/d lpgrouskmass suitable of paraformaldehyde present, by weight, in the reaction mixture, should be less than 5% and preferably 3% or less, such as between about 0.1% and 2%. This para for a variety of important uses. More speci?cally, it 10 formaldehyde, in addition to promoting water-insolubility, irelates'to'foanredmassesproduced by interaction at am also acts to trigger the expansion of the reaction mixture bient temperatures of water-soluble inorgaic il' 4 in certain cases, as well as to accelerate the foaming rate. . _ ' general] in The fourth in ‘m, which, though not necessary _ presence 0 ow - -- inorgam ers, and n, a ound suit— in -v.- - daisW abte 'i’6rT1se“'as"f6ai?Ed1iiiIpT5€eTi'?§u'iation and in other 15 insoluble pro ucts, wk; preferably an inorganic and ~ valuable outlets. .generally an inert refrac "material such as alumina, In the case of thermal insulation, for example, indus magnesia, Wm, ?reclay, graphite trial usage thereof for many years has been limited be or__coml5ination_thereof. ltis usually employed in pow- 9 cause of the di?iculty of shaping the commercially avail dered form, preferably as a ?our of 200 mesh or ?ner, in able solid materials to ?t the speci?c needs involved. 20 amounts of about 0.1% by weight up to 20%, 30%, 40% Until recently, such insulation was available only in the or 50% or more of the composition. form of powder, sheet (?exible and rigid), and block. The reaction of the present invention may be con trolled to produce a water-soluble or water-insoluble solid material to the desired form for the particular applica foamed product, as desired. The in-situ foaming causes tion. This led to the unfortunate results that high labor 25 an increase in volume of the mixture, following which costs would be involved and that the efficiency of the in a hardening of the foam occurs. Roughly, an increase sulation would not be at its optimum due to the inherent in volume of 3 to 1 results in forming a solidi?ed foam di?iculty in ?tting closely the product to be insulated. of density of about 40 lb./cu. ft., while an increase of 6 In the past few years, light-weight foamed-in-place in to 1 results with a product density of about 18 lb./cu. ft. sulation became available and it was received enthusiasti 30 The reaction mixture to rodu ater-soluble hard Accordingly, it was necessary to fabricate (shape) the cally by industry because of its many advantages. Un ed foam product contains a peroxy compound, and fortunately, these rather expensive foamed products have been composed of organic materials which necessarily limit their usage to low operating temperatures. Also, _ both hquid water-soluble and powdered water-soluble . S?iwewW the foaming reac n. 1 s atter. ingredient,’ , they require control of the reaction composition to rather 35 ' e ing takes from 10 to 24 hours with no narrow limits, and usually heat has been necessary to gen appreciable evolution of heat, m the ingredient erate the gas from the “blowing” agent in the production in amounts of from 1% to 5%, foaming takes place in of such foamed masses. These temperature limitations from 5 to 60 minutes, with some evolution of heat. The and installation di?iculties under industrial conditions ' t ratlo "-71 is water-solu - ' -. ' have emphasized the need for a simple, light-weight, foamed-in-place product which would be resistant to heat greater than 3 to 1 Density of the oamed product may and would not require external heating for the foaming "' E controlled to be from 10 to 30 lb./cu. ft., depending reaction. upon the proportions of the ingredients and the amount I" According to the present invention, there is produced an essentially inorganic foamed-in-place (or in-situ foamed) product suitable for use at elevated tempera tures, which is competitive price-wise even with the archaic powder, sheet, or block type of material. The ?rst ingredient in the c mposition of the present -- ' - " . - 0 araformaldeh of paraformaldehyde used. d - - » _ In the preparation of a water-soluble hardened foamed 45 product, a liquid comprising about 5 to 20 parts by weight par‘t’s‘b'y of a wategsg?ileiiq?dfpero weight of anliqui‘d'wa‘t'eif-sqipyle?cate, and is mixed with about 10 to mam-ty'?eigm of powdered water , which is a peroxy soluble silicate. It is generally desirable to add about 1 50 to 5 parts by weight of paraformaldehyde to accelerate the foaming rate. The liquid portion is mixed with the powder, then the slurry is stirred until smooth and creamy, and it is poured into the cavity to be ?lled. No e second ingredient is a WWW silicate serving (in ?nished form) as the skeletal struc ture and further processing is required. 55 (when I - M -- T'n mass. are submitted: This ingredient is employed inmmlggnor liquid form, as will be explained further, and it is’the proportion of this component in relation to the third ingredient, which determines whether 60 the resulting foam will be water-soluble or water-insolu ble. Particularly effective, are the-alkali metal siliates; x such as those 0 The third ingredient, w c may be omitte in certain special cases (i.e., in water-soluble products where foam ing time duration is unimportant), as will be explained ' - - It appears to act in_a catalytic mann'é'r, oth to promote insolubility and to ac celerate the foaming reaction. In the case where sodium silicate is used together with paraformaldehyde, there is a critical weight ratio of concentration necessary to pro To illustrate the e?fect of various ingredients on the properties of the foamed product, the following examples s the adhesive comound to bind the filler Example Number Material 1 Sodium Silt e (Powdered) ' 7: - - - - Powdered),pereent - . __ i I 1-5"! I"- 45 43 45 0 2 0 e (30% Aqueous), __________________ __ 10 Sodium Silicate (Liquid) (“N" Brand 1.0Naz0:3.22 Si0z),percentb weight 45 Density of foamed product, lb. cu. ft... Water Solubility _____________________ __ 70 Radio oi NazO/Paraiorm?ldehyde .... .. 1 N o foaming. 3 ("G" Bran — . az0:3.22 Bios), percent by weight .......................... -65 2 1 Very soluble. ‘ 18 (i) In?nite 10 5 45 50 40 ' Soluble None 6-1 In?mte 3,095,312 3 Il The product of Example 1 has a uniform multicellular structure, and is readily soluble in water, resistant to ples 7 and 8 illustrate the need for both paraformalde hyde and peroxy compounds to cause full foaming. The second type of water-insoluble foamed product ?ame impingement and capable of withstanding continual exposure of at least 10 minutes to temperatures of up to made in accordance with this invention involves use of a reaction mixture comprising a powder mixture of 1200° F. The product of Example 2 (to which mixture paraformaldehyde was added to accelerate the rate of paraformaldehyde (essential to this type of foam) and foaming) possesses the same properties except that the an inert organic ?ller. This powder is admixed with an structure of the material is coarse, and the product shrinks aqueous liquid comprising a peroxy compound, also a on solidifying. Example 3 illustrates the fact that the liquid water-soluble inorganic silicate, and water. The peroxy compound is essential to foam production. With 10 prepared powder mixture is combined with the aqueous out it, the mixture does not expand upon reaction. mixture of peroxy compound and water and the resulting Such water-soluble solidi?ed foam products made in paste is ?nally mixed with the liquid water-soluble sili accordance with the present invention have a number cate. The foamed product resulting from the reaction of important uses, such as in making temporary molds is water-insoluble (the ratio of Nazo to paraformalde for plastic boat bulls, and for other similar purposes 15 hyde being less than 3 to 1), and its density can vary wherein an empty cavity is desired upon completion of from 20 to 50 lb./cu. ft. Foaming time may be made to the plastic or other type of article to be made (wherein take place in about 5 to 60 minutes after the initial mix the solid foam is leached out with water). The low cost ing (with slight evolution of heat) by control of the of such foams makes them expendable. amount of paraformaldehyde used. There are two types of water-insoluble foams which 20 In the preparation of such water-insoluble foam, a may be prepared in accordance with the present inven powder comprising about 1 to 5 parts by weight of para tion. The ?rst type involves use of a powder mixture formaldehyde and about 20 to 50 parts by weight of an of a peroxy compound, paraformaldehyde (which is es inert inorganic ?ller is mixed with a liquid comprising sential to this type of foam) and an inert inorganic ?ller, about 5 to 15 parts by weight of liquid peroxy compound which powder then is admixed with a liquid water and 5 to 15 parts by weight of water, and the resulting soluble inorganic silicate. The product produced by paste is further mixed with about 15 to 70 parts by weight interaction of these ingredients is a water-insoluble foam of a liquid water-soluble silicate. The ?nal reaction slurry (the ratio of NazO to paraformaldehyde in this case then is poured into the cavity to be ?lled and no further being less than 3 to 1). Densities of the solid products processing is required. vary from about 20 to 50 lbs./cu. ft. Su?’icient para 30 To illustrate the effects of the various ingredients on formaldehyde is employed so that foaming occurs rapidly the properties of the foamed product, the following ex in about 5 to 60 minutes after the initial mixing, with amples are submitted: slight evoldtfé‘n'iaf'heat. In the preparation of such water-insoluble solid foams, a powder is mixed comprising about 5 to 30 parts by Material Example Number weight of a solid peroxy compound, about 1 to 5 parts of paraformaldehyde, and about 20 to 50 parts by weight of an inert inorganic ?ller. Then, this powder is mixed Silica Flour (200+ mesh), percent by weig _________________________________ __ with about 15 to 75 parts by weight of a liquid, water (Powdered), percent by soluble inorganic silicate. This reaction mixture is stirred 40 Parafoil'lmaldehyde eig t ................................. .. until it is smooth and creamy, and it is then poured into . lg the cavity to be ?lled. Water, percent by weight No further processing is required. To illustrate the e?ects of various ingredients on the properties of the foamed product, the following examples 45 are submitted: Sodium Silicate (Liquid), (9% N810), “N"Brand 1.0 NaiO:3.22 sioa), Percent by weight Density of Foamed Product, lb./cu it Water Solubility _______________ _. Ratio of N rim/paraformaldehyde ......... __ 1 Little foam. Example Number Material 4 6 6 7 8 Silica Flour (200+ mesh), per cent by weight ............ __ Paraformaldehyde (Pow dered), percent by weight-" “Sodium Perborate Silicate N 32 0 1 3 0 3 (Pow dered), percent by weight-.. “Sodium 40 16 ‘ (Liquid) (“N" Brand 1.0 NazO:3.22 SiOr)I percent by we1gbt._.. Density of Foamed Product, 1 N o foam. The product obtained from Example 9 has a uniform 50 multicellular structure. It is insoluble in water, is resist ant to ?ame impingement and is capable of withstanding continual exposure of at least 16 hour to temperatures of up to 1400° F. Examples 10 and 11 illustrate the interdependence of paraformaldehyde and peroxy com 55 pound to promote full foaming. Example 12 shows the need for solid ?ller to be utilized in order to form a rigid fully foamed product. 51 All of the aforesaid three types of foamed products (one soluble and the two insoluble) are readily repair None Soluble Slight 60 able or “weldable” by addition of foam slurry (e.g., the Ratio of NmO/Paratormalde 1. 5 4. 6 2. 4 hyde ...................... -. mixture before setting) to any defect and/or cavity which requires subsequent ?lling. Such “repairs” form a con 1 Little foam. 1 No foam. tiguous, adherent structure that maintains the essential characteristics of the initial foam. The product from Example 4 has a uniform multicellu 65 Another facet of this invention is the substitution of lb.lcu. ft ................... ._ Water Solubility ____________ . lar structure. 45 It is insoluble in water, is resistant to some or all of the inert organic ?llers mentioned in the ?ame impingement, and is capable of withstanding con~ examples, by use of an oxidizable powdered solid, such as graphite, carbon, wood ?our, etc., which may be tinual exposure of at least 10 minutes to temperatures of up to 1200° F. The product from Example 5 has similar properties, but it is soluble in water, as is evidenced by the ratio of Nap/paraformaldehyde. The product from Example 6 has similar, but somewhat less refractory burned to produce an exothermic reaction. Such an exothermic reagent has utility in the ?eld of “hot topping” of metal ingots; i.e., use as a monolithic foam in place of fabricated refractory forms used to provide heat to properties, higher density and only slight solubility in cast metal bodies for feeding shrinkage cavities. water. The Nap/paraformaldehyde ratio of 2.4/1 is a It will be noted that, among the other advantages of borderline value with respect to water solubility. Exam 75 the present solidi?ed foam material over prior art mate 3,095,312 high operating temperatures, light-weight, excellent cavity ?lling properties, shock resistance, and excellent insula tion properties. 6 I claim: 1. A process for producing a water-insoluble light rigid porous rapidly-foamed product having a multicellular rials, there are included low cost, ease of preparation, lack of corrosive properties, no need for external heat, structure consisting essentially of mixing together in an aqueous medium at ambient temperature about 1 to 20 Furthermore, it is possible to foam parts by weight of a gas-producing peroxy compound, about 30 to 135 parts of water-soluble inorganic silicate. and about 1 to 5 parts of paraformaldehyde, while main taining a silicate/aldehyde weight ratio between about additional material on to already-foamed solid so that the two become welded into a monolithic mass of high tenacity. This is of importance in repair work where cavities and broken parts require mending with additional foam. 10 1.26 to about. 2.4 (expressed as NazO/paraformaldehyde) . 2. A process according to claim 1 in which up to 50 The foams of the present invention have advantages parts of an insoluble ?ller is added to the reaction mixture. in ?lling cavities to be insulated against heat, cold, or sound, and in providing intimate contact for more effi References Cited in the ?le of this patent cient insulation as compared to the ?tted types. Also, UNITED STATES PATENTS the foam may be generated in ?ab slab forms or as molds 1,832,752 Thoretz _____________ __ Nov. 17, 1931 for the production of acoustical panels for ceilings and 1,944,008 2,018,632 similar uses. The reactions involved in the preparation of the foam are not clearly understood, but it is believed that the ex pansion element is oxygen, the source of which is the 2,117,605 2,234,646 2,284,400 2,921,357 2,988,454 peroxy compound. The paraformaldehyde is believed to be decomposed or volatilized in the reaction, so that the ?nal product consists mainly of hardened silicate and ?ller (if used), which are the essential ingredients of the 16, 1934 22, 1935 17, 11, Llewellyn et a1 _________ __ May 26, Fujii et a1 _____________ -_ June 19, Aberegg _____________ ..- June 13, 1938 1941 1942 1960 1961 FOREIGN PATENTS ' ?nished hardened foam product. 399,367 Other materials which may be added to the powder or liquid ingredients, or to both, prior to foaming, in ‘Great Britain __________ __ Oct. 5, 1933 OTHER REFERENCES Mellor: “A Comprehensive Treatise on Inorganic and clude other exothermic reagents, soluble dyes, pigments, re?ective ingredients, such as aluminum and magnesium ' ?akes or powder, and the like. Hobart _______________ _- Jan. Boller _______________ .... Oct. Fowler ______________ __ May Humphries ___________ _... Mar. 30 Theoretical Chemistry," publ. 1925, Longmans Green & Co., London, vol. VI, page 334.