DE1694604A1 - product - Google Patents

Description

M 2150.

Minnesota Mining and Manufacturing Company Saii.t Pcul, Mini es ο ta 55101, V. St. A.

product

Dieae iirfindurig bezii.hu on very solid materials of low density, uei dene.t Λα Hax'Z ^ Systeni with micro Hohlglaskügelcheu iüt filled uekannt in dex 'art as syntactic foam, and to re-giesöbi compositions from which such foams be made i-. önneri.

; -xikro-houlkt% elehen have already been used for the production of resin systies with low density ve X ¹ Vf ends j see, for example, the USA-Patentuohr'if ν ^ 0 ^ 0 215 by Veatch et al., published on 17. April I962. DX ^ öo foams differ from the Uolichen foam plastics, uei which a blowing agent is used, dadurci that the

10081072006 "

New bobbin thread ιαπ, / α. »^ - ^.« - » ^^^ <^ nm _in wv4.% Mn

"- 2. -. M 2150

Empty spaces are much more uniform in size and much more uniform are distributed.

There has been a need for lightweight materials for manufacture of vehicles for space travel and deep-sea research. However, these require. It is also used in an all-over-the-world market Compressive strength of the material, and in case of application in deep sea research., Resistance to water absorption under strong hydrostatic. Pressure. Low density material that was previously used had avenged the demanded Compressive strength, see e.g. column 9 of the above The Veatch et al patent disclosing material having a compressive strength of 23.20 kg / cm '". To produce foams with greater compressive strength, glass beads were used with "greater density used, t.ber as a result the density of the material increased by 0.72-0.80 g / ciir. This Material was heavier than expected. in the application for a submarine the flotation material is so large in volume. lumen that only a small proportion ε, η transported load could be. . '

It is the object of the present invention to produce a syntactic foam that is substantially free of voids except for those in the microsphere which has a low density, less than about 0.673 g / cm * the tough ge, _: , en hydrostatic and uniaxial compressive forces of / 250 - 700 ■ kg / etn or more, and which is less than 2 wt. , and in general

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less than 0.5% by weight of water absorbs when it is in direct contact with water under high hydrostatic pressure (ie at least 350 kg / cm). The foams of the present invention can be cured in the form of thick sections, ie in cubes with an edge length of 30.48 cm or size ¹ , without the material shrinking or experiencing any other build-up in the middle of the cross-section.

The features and advantages of the present invention are set forth in generally achieved by having a mixture of a polymer that has a high resistance to pressure force and a high one Has molecular weight, like "ζ; B. An epoxy resin, including the necessary activators or catalysts, and from microspheres with great strength and low density.

The resins useful in practicing the invention are said to have a high molecular weight, a Barcol hardness of at least 35> a compressive strength of at least about

ρ ρ

700 kg / cm, and preferably at least 1050 kg / cm, a Young

2 have a modulus of at least about 21,000 kg / cm and a water absorption of less than about 0.5 ¹ P after immersion in water at 25 ° C for 7 days ("ASTFHPes.t D5 |; 5-52T). Epoxy resins Resins which can be used with little loss of strength are polystyrene, polyesters, polyurethanes and copolymers and / or mixtures thereof. A particularly suitable epoxy is that of Wear et al. in US Pat. September 1962 the type described at room temperature

BUILDING

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1894604

is quite inactive, but is transformed into a tough, hard solid by brief heating to a suitable temperature, • In short , these preferred masses mainly consist of a mixture

(1) An epoxy resin (e.g. a polyglycidy lather vsihes polyvalent Phenol) with more than one 1,2-epoxy group average molecular weight,

(2) .an anhydride of a polycaroonic acid in a sufficient amount Proportion that about 0.5 - 2 anhydride groups per 1,2-j £ po \ ydgruppe omitted, this amount of anhydride being dissolved in a liquid polyglycidyl ether of a polyhydric phenol, so that masses arise that are liquid oleioene at room temperature, and

(j5) an alfine catalyst.

Preferred polymers for practicing the present invention are highly crosslinked, thermoset materials which, for example, in the case of the preferred epoxies, are of near infinite molecular weight. The physical properties set forth above which are required of the resin, can be reached, in general, on Oesten by highly cross-linked material having a molecular weight of at least 100 000th Jeuoeh are also certain long-chain, thermoplastic materials, - s..i. certain classes of polystyrenes and polyurethanes and equivalents thereof are suitable therefor.

To make the foams of the present invention, should

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the polymeric materials must be of a fluid consistency. For the pail of castable masses of resin and microspheres the viscosity can be less than about 100,000 centipoise. For the In the event that the resin is braided into the microspheres under pressure, the viscosity of the resin should preferably be below from -ö-tvfa 000 centipoise at the pike temperature. These Properties can be due to aging of the resin composition, due to the ratio from resin to microspheres, by temperature, etc. ^ taxes were. In the case of the thermoplastic resin compositions achieved ma: the flowable viscosity by making the resin a; hr.tilts and continues to heat until the viscosity reaches the is reduced to the respective degree.

The glass microspheres required for the present invention :; have a diameter of about 5 - 300 microns, they must have high compressive strength and yet have a true particle density ur: terhal; j of 0.4 ^ m / aver on average.

The preferred microspheres are made from Gks with "high SiQp-Gexialt, ie from a glass which " contains "at least 0 % by weight. The microspheres have to water very wi>-derstur;a; be ifähig jnd in dex · able boiling water Io 3tufid ', n (ie, overnight) with a weight loss of wejii / ^ or ale ^ i' / at least: to viidorstehe , n.

LIo ijcvoi'zugton Mik / -okugelehen are extended particles νυη feüt ';i'i vo Vt / .i L'or internal glass, daa by reheating the preformed

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Glass particles are brought into spherical shape at elevated temperature so that the glass is softened and gases are absorbed, a. ;. HgO, COp, SOg, etc., which cause the particles to expand (See U.S. Patent 3,365,315, January 23, 1968).

Two microspheres are to be used that have been surface-treated to improve the adhesive strength of the resin on them, ζ, 3. with - an aminesilane, an epo.iysilane or a chronicle complex of the Werner type --ir, alcohol. (e.g. " " Volari ", methacrylate-chromic acid chloride). Such the adhesion strength improving agents allow the formation of firm and uniform bonds between the "Mikrokiigelchen and the shark ^j z-matrix ,, which is important for the formation of a void-free. Matrix.

The foams of this invention are obtained by using the glass microspheres in proportions of about. 15 to about βθ wt .- ^ of the resin or nearly 55-90 volume- ^ used. When processing and .d Great care must be taken to deform the composition of this invention to ensure that the polymeric matrix is essentially is free from other berries than those in the microspheres are included * It is believed that if left behind, ir- I Regardless of the pores in the matrix due to the inclusion of air, these voids form channels when the material is under high pressure • is exposed to water or other liquids can penetrate.

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The one process * around the basic mass (matrix) free of voids to manufacture * is, that in one chamber so much Mlkroküg- lehen to be filled until it is completely filled, the Air is evacuated from the interstices and the hardenable the Basic mass formed mass filled into the evacuated chamber

man

v.'ird, the liar's can / with the help of gravity and / or capillarity i.-i let the voids flow between the microspheres. Ir; In some cases the resin came into the water with the help of capillarity ! ■ microbeads penetrate without a vacuum turn. The resin is then hardened and you get a product that you can further cut can ο (ϊ3Γ if the chamber hsfcfce, exact dimensions can maii use the casting as it was shaped.

The preferred method of making pore-free moldings is to mix the resin compound and microspheres together with an agent that tends to separate the microspheres ^! low density from the resin or prevents flotation in it without the viscosity of the mixture increasing noticeably. For the sake of simplicity, sole agents are referred to below as "enti-levitation agents". The mixing is carried out in a vacuum to safely remove all air, and the resulting mass can be poured directly into any kind of mold, or, according to a preferred embodiment of this invention, in the uncured state for later glassing Trade brought wei'deri. The hardening of the polymeric green mass can take place later, for example by turning the masc ·. inVcUjr form to a corresponding moderately increased temperature,

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generally in the range of 121-176 ° C. After a other processes can be used to create systems that use a hardening agent included that within a short time after the Giesseo Cure at room temperature. Careful Ausvialilo.es anti- Suspending agent is necessary because the majority of the products that could fulfill such a function act as gelling or thickening agents act that - even if they are only present in small proportions - the viscosity of the mixtures to such an extent increase that they are no longer pourable.

A particularly suitable material is called "Bentone 11" traded by the National Lead Co. and consists of needle-like particles of montmorillonite clay that are filled with a quaternary Ammonium salts are coated in the Vieise that the Natriui :: - and calcium ions on the surface of the dairy particles through quaternary Ammonium cations are replaced. The method for coating clay particles with an amine is described in U.S. Patent No. 2,531,427 of November 28, 1950 - described (see also "Kolloid-Zeitschrift" 1 ^ 1, No. 1, pp. 40-48, 1954). The coating on the Clay particles give the anti-floating agent a certain catalytic effect Effectiveness, which is able to fulfill a double function. If the clay parts in the resin are in the correct V / e are distributed, they are in "form, of agglomerates ^ nit a 5. Micron (or smaller) size available. Another important thing Anti-floating agent is finely divided silica having a particle size of 0.01 to 0.02 microns, "preferably 0.01"> Micron,

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In order to generate the mixing of the Micr okiige uring and erMehtern of the resin and a ^ iesscares system ,, the viscosity of the Mischur ^ j oei a temperature of less than .Approximately 9 ^ to - C ^ r not ös is ar - Is .. about 100,000 centipoise, and preferably less than about 50,000 centipoise. The viscosity is dependent au a erheoli- oa-iti measure of the ratio of the resin to the microspheres, the front resin system used type Gis and the veiwendeter · Antisciiwu.jemittel and it will be clear to the skilled person that various combinations of these ingredients for making von Massel; of this invention are suitable.

The experience is further illustrated by the following examples, whatir. all parts, if not mentioned otherwise. Weight parts are.

A resin composition was obtained by mixing the following ingredients

■ parts

Polyglycidyl ethers of a polyhydric phenol

(, akeli'te iCRL-2774 epoxy resin) 59.8

Hcthyi ~ endo-ois-Mcyolo- (2.2, l) -5-hepten-2,3-dioavuonic anhydride (Crosslinking agent) 58.7.

Or ... ·: .- iIsohos derivative of a water-containing Magne- L Lun- / ilumi "aium-Sllikats with a polyamine as o ^ erflluilienaktivurn agent (Bentone 11, Antlcchv; oi; emlttol)" 1,5

■ '1,5' f '-.- il ·, U' ^ r * Harzma.'iso were mixed with 28.5 parts of egg mlnne- : ota I-'ILrii-iiij, ari'i kanu fao door ing company manufactured hollow glass bead

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address type i.5j55A, prepared according to US Patent 3,365,315, mixed whose Teilcher.grösse i \: \ range of 20 microns, which cut an average particle size of 40 microns and a specific gravity of about 0.34 g / cm ^, and treated with a 1; jigen aqueous solution of Yolan A, a complex of the Werner type (methacrylate chromic acid chloride in isopropanol). The mass was mixed vigorously in vacuo until the microspheres were uniformly distributed in the resin. The cured mixture usually became liquid again after being reheated to about 60 ° C after being stored for 4 weeks at room temperature and 6 months at a reduced temperature of 5 ° C, and could therefore "be treated in the uncured form. A Giesslii g in the form of a cube of 30.5 e-rn edge length was prepared by mixing egg part of the mass 65 ° C was cast directly after mixing in a metal mold ge ^, gradually heated within 24 hours to I7I ⁰ C, 8 Maintained for hours at 171 "G and was cooled with a temperature gradient of 14 ° C for 4 hours. After cooling to room temperature, the casting was removed from the metal mold. The casting obtained had a density of about 0.672 g / cm- ^ with a vertical density gradient of only about 0.016 g / cm "'. In 25.4 mm-ViUrfei absorbed less than about 2 g / cm of water afterwards he with all surfaces for 1000 hours direct contact with Viasset '. under ■ a pressure of 770 kg / cm had The material has a _RIE, ungsfestigkeit of about 420 kg / cm, a ISiegunrörnodul of about 282IO kg / cm'"" a tensile strength of about j32i 'kg / oin "', too, - modulus of rigidity of about 3II50 kg / cm ^1" ο ine uniaxial Di'uck-

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strength - of about 90 kg / cm, a uniaxial pressure module of

about 335 * 500 kg / eisf "and a hydrostatic collapse pressure (collapse pressure) of about 1225 kg / cm.

Example 2

A resin composition was obtained by mixing the following ingredients

manufactured; ".

Parts "

Polyglycidyl ether of polyhydric phenol

(Bakelite EEL-2774 epoxy resin) 60.6

Methyl-endo-cis-bic3 ^r clo- (2,2,1) -5-hepten-2,5-dicarboxylic acid anhydride (crosslinking agent) 39Λ

Glass microspheres with an average particle density of 0.196, whose diameters are in the range of 20-174 microns, and whose average diameter is less than about 55, are filled into a cylindrical mold (6j.5 inner diameters - ^ 5.7 ram height) and by shaking tightly. The beads were held at the top and bottom of the vessel with the help of fine-meshed cloths (e.g. cheesecloth) or sieves. The resin is poured into the beads by placing the cylindrical shape in a trough at 60-107 ° C The atrnospheric pressure forces the resin through the capillary spaces of the packed spheres, deeply moist and surrounded by resin on 176 ⁰ G oi'hitat to initiate the curing. The temperature was a few> n #oi XV'6 "" i ^ Iialton urr.i darm the form and the Giesi

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cooled to room temperature. You get a very solid, syntactic one Low density foam drawn with HA and its properties are summarized in Table I. .

A foam ¹ was made according to the procedure of Example 1, except that the microspheres had a true particle density of 0.196 g / cmtr. The properties of the foam obtained, which was designated ¹ with ILSS, are summarized in Table I for comparison. The stated values are the average values of several samples.

Table 1 . ·

Property vacuum. Mechanical

Mixing impregnation

. HA HB

Density (g / cnr ⁵ ) 0.52.8 0.576

Uniaxial compressive strength. -

(kg / öm ² ) 623 672

Uniaxial pressure module (kg / cnf ") 24 500 2o 6OO

Uniaxial 0.2 % offset

Yield point (kg / cm)

Hydrostatic tensile strength
(kg / cm)

Water absorption in wt .- ^ o after one

weekly exposure at about 350 kg / cm 1.5 1.3

(kg / cm ² ) x 809 882

- Claims 109818/2006

Claims (1)

M 2150 patent application back: 1. Uncured, a curing agent-containing epoxy resin system _{which is filled with 55 to 90 Vol T} # glass microspheres of 5 to 300 microns in diameter, characterized in that the system filled with microspheres is castable and essentially free of entrapped air, a viscosity of is less than 100,000 Gp at a temperature below 93 ° G and further contains an anti-floating agent which is either finely divided silica or acicular particles of a clay coated with a quaternary amine. Filled resin system according to claim 1, characterized in that the antisonic agent in the filled Ilarz system in one iiofi I-lcngö voi'lianden is that the equal advantage Mik: ··)! 'Ügolohon In dom- geaarnton, filled resin system at least 'snd oirieü is maintained for a period of days. BATH 109818/200 6 j5. Filled resin system according to claim 1 or 2, characterized in that that the filled resin system has a viscosity of less than 50,000 Cp at 93 ° C. Me / -ir,. 109818/2006