IL41563A - Polymer compositions having reduced smoke forming capacity and their production - Google Patents

Description

VoS i m compositions having reduced smoke forming ca clty and their production 564 The present invention is related to polymer formulation additives which impart surprising reduced smoke production to the plastic product upon combustion. The present invention is more particularly directed to the use of iron based metallocenes, e.g. dicyclopentadienyl iron (ferrocene) and derivatives thereof, as smoke suppression additives in plastics, particularly polyvinyl chloride plastics and poly-urethane foams.

Dicyclopentadienyl iron (ferrocene) has been used as a smoke reducing additive for hydrocarbon fuels - see U.S.

Patents 3,294,685 and 3,341,311. This body of art is directed to the use of ferrocene and derivatives thereof, as a combustion catalyst to increase the quality of fuel combustion and, therefore, is directed to the increase of the overall flammability of the fuel.

Dicyclopentadienyl iron has also been employed as a flame retardant additive in polymers but in conjunction with chlorine and/or bromine containing compounds and, often, phosphorus and antimony containing compounds - see Belgium Patent 621,125 and U.S. Patent 3,269,963. Although smoke reduction in polymers has been disclosed with other, unrelated additives -see British Patent 1,080,468 - it is generally well-known that the use of flame retardant additives, e.g. ferrocene, in polymers, often leads to increased smoke production - see papers by Einhorn and Gaskill in the University of Utah Polymer Conference (June 15-16, 1970), pages 29, 52.

It is not surprising in view of the foregoing that the incorporation of ferrocene in, for example polyvinylchloride has been limited and for the reported purpose of studying U.V. stability - see J. Appl. Poly. Sci. .12(7), 1543 (1968).

Now it has been discovered that polymer materials,, particularly polyvinyl chloride plastics and polyurethane foams, can be significantly improved (suppressed) in smoke production potential upon combustion by the addition of a certain effective amount of dicyclopentadienyl iron or a substituted derivative thereof, as defined in more detail hereinafter.

The present invention thus provides plastic products characterized by having improved smoke suppression properties by the addition of compounds which are themselves non-toxic components of the final products.

The present invention thus is directed to the use of a dicyclopentadienyl iron compound as a smoke suppression additive in a polymer. The present invention provides the use of a dicyclopentadienyl iron compound in a polymer in a smoke reducing effective amount. The present invention further provides a method useful for reducing the smoke production of a polymer upon combustion which comprises incorporating therein a smoke reducing effective amount of a dicyclopentadienyl iron compound.

Useful dicyclopentadienyl iron compounds include dicyclopentadienyl iron (ferrocene) ; mono and di lower (1 to 8 carbons) alkyl dicyclopentadienyl iron compounds, e.g. ethyldicyclopentadienyl -iron, n-butyldicyclopentadienyl iron, diethyldicyclopentadienyl iron, and di-n-butyldicyclopenta-dienyl iron; mono and di lower (1 to 8 carbons) alkanoyl dicyclopentadienyl iron compounds, e.g. acetyldicyclopenta-dienyl iron, butyryldicyclopentadienyl iron, diacetyldicyclo-pentadienyl iron, and dibutyryldicyclopentadienyl iron; the drmer and polymer reaction products of dicyclopentadienyl iron and lower (1 to 8 carbons) alkyl substituted derivatives thereof with aldehydes or ketones, e.g. 2 , 2-di (ethyldicyclo-pentadienyl iron) -propane, di (butyldicyclopentadienyl iron) -methane, di (dicyclopentadienyl iron) -methane - see also U.S. Patent 3,437,634. The higher molecular weight dicyclopentadienyl iron compounds are characterized by lower volatility properties which offer the advantages of lower volatile loss of compound upon storage of polymer product.

In the present invention, by the term "smoke reducing effective amount" is meant that amount of the dicyclopentadienyl iron compound which will effectively suppress the amount of smoke produced upon combustio of a polymer product when incorporated therein. In general, amounts of from about 0.1 to about 1.0 percent of the dicyclopentadienyl iron compound by weight of the total polymer composition are useful. Preferred amounts range from about 0.25 to about 0.5 percent by weight.

Polymer products useful herein include vinyl chloride homopolymer or copolymers containing a minimum of about 50 percent vinyl chloride polymerized in accordance with known methods whether anionic, cationic, free radical, or Ziegler induced and the hydrocarbon polymers having a nitrogen atom containing backbone, i.e. the urethanes. One particular system is a polyurethane polymer formulated to produce a durable, low density foam. A greater degree of crosslinking in urethane systems increases the smoke reduction response upon addition of the additives hereof. This is pertinent to the high resiliency or cold cure urethane foam systems which are also flame retardant due to their high degree of cross-linking.

The polymer product herein can be optionally modified with components which improve various physical characteristics such as plasticizers , flow additives, fillers, release agents, pigments, stabilizers, anti-oxidants, and so forth, or other ingredients, such as barium sulfate, aluminum chloride, metal stearates.

The smoke suppressed polymer products hereof can be prepared in accordance known method including simple blending or by milling, molding, or extrud-ing the components. The dicyclopentadienyl iron compound may also be added during the polymerization process provided the components or other process conditions are mutually inert.

The polymer products of the present invention are useful for the same applications as the parent polymers are known to be used, i.e. in automobile and airplane parts, containers, appliances, electrical devices, furniture, bedding, and so forth; and, by virtue of the present invention, are particularly useful in those applications wherein toxicity and/or smoke production upon (accidental) combustion is particularly to be avoided, such as in building or transportation vehicle parts, furniture and bedding materials.

The following examples further illustrate the present invention.

EXAMPLE 1 A series of three (0, 1 and 2 percent) ferrocene solutions in the dimethylether of tetraethylene glycol are prepared. Polyvinyl chloride (PVC) samples are then immersed in these solutions at 100°C for 15 minutes, then placed in boiling water for 15 minutes to extract the solvent, and then placed in an oven at 110°C for 15 minutes to dry the sample The dried samples, containing 0, 0.3 and 0.6 percent , respe tively, of ferrocene, are then tested by use of. the ASTM D635-63 flammability test modified by employing a fume hood and vacuum source separated by a filter paper membrane collector. The vacuum collection system used to trap the smoke generated on combustion provides the following result Sample Solvent Solvent + Solvent + Treatment Only Ferrocene Ferrocene Weight loss of PVC sample on combustion (mg.) 486 339 372 Carbon particles collected in smoke system (mg.) 17.6 6.5 4.9 EXAMPLE 2 Rigid polyvinyl chloride containing cadmium stearate is formulated as in the following table and the formulation tested in a configuration similar to that of Example 1 and burning the sample within a combustion chamber with a chimney and filter paper collector. A 30 second flame exposure followed by mechanical debridement provides burning weight and smoke data.

% Smoke : Burning Rate Smoke Generation Smoke Wt. v Formulation mg. /min . Rate, mg./min. Wt. Burned No Ferrocene 610 31 5.1 0.125% Ferrocene 430 12 4.4 0.250% Ferrocene 420 9 2.1 0.50% Ferrocene 460 10 2.2 EXAMPLE 3 A flexible polyvinyl chloride system containing 60 percent PVC, 40 percent plasticizer, 0.5 percent styrene oxide, and 0.25 percent hydroquinone is formulated as in the following table and tested as described in Example 2 with the following results: Smoke Genera¬ Formulation Burning Rate tion Rate, Ferrocene Plasticizer mg . /min . mg. /min . % Smoke None Dioctylphthalate (DOP) 600 24 4.0 0.25 Dioctylphthalate 620 13 2.1 0.50 Dioctylphthalate 720 18 2.5 None 10% Tricresyl- phosphate 400 24 6.0 + 30% DOP 0.25 10% Tricresyl- phosphate 520 18 3.5 + 30% DOP 0.50 10% Tricresyl- phosphate 580 16 2.8 + 30% DOP EXAMPLE 4 A rigid polyurethane foam based on diphenylmethane diisocyanate and a-methylglucoside polypropylene oxide poly- 3 ether polyol is prepared having a density of 2.5#/ft. . The foam is tested by the procedure of Example 2 using a 10x10x10 mm. cube which is completely combusted with 30 second flame exposure to give char with the following results: % Smoke ί ASTM D-1692 Smoke wt . Rate Ferrocene 'Amt . Burned x 100 Burning in. /min.

None 7.6 11 0.4 6.8 7 0.8 5.7 10 EXAMPLE 5 The procedures of Examples 1 to 4 are repeated using each of ethyldicyclopentadienyl iron, n-butyldicyclopenta-dienyl iron, 2 , 2-di (ethyldicyclopentadienyl iron) -propane , and the polymeric reaction product of ferrocene and methylol containing approximately 29 percent iron, in lieu of dicyclo-pentadienyl iron (ferrocene), with similar results.

Claims (1)

1. insufficientOCRQuality