BE1003938A5 - Dust control of open by solid aromatic anhydrides. - Google Patents

Abstract

Method for weakening dust generation by solid aromatic anhydrides, in which the anhydride is treated with an organic compound which is both liquid and substantially non-volatile at normal ambient temperatures and pressures and which does not contain functionality anhydride, the aromatic anhydride being present in an amount of from about 90 to 99.999% by weight and the organic compound being present in an amount from about 0.001 to about 10% by weight, based on the total weight of the composition.

Description

       

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   Elimination of dust released by solid aromatic anhydrides.



  Background of the invention.



    Field of the invention.



   The present invention relates to the suppression of dust released by aromatic anhydrides. More particularly, the invention relates to the removal of dust released by solid aromatic anhydrides by treating them using an organic compound.



  Known state of the art.



   Aromatic anhydrides are useful industrial chemicals. Many of them are produced and used annually by millions of kilograms. For example, trimellitic anhydride (TMA) is used in the manufacture of plasticizers for vinyl polymers which can be used for insulating sheaths for electrical wires, joints in refrigerators, upholstery for cars and furniture, tablecloths washable and pool liners. TMA is used in water-soluble alkyd coatings. It is used to manufacture polymers for high temperatures, such as amide-imide polymers. TMA is used as a curing agent for epoxy resins.

   In addition, its derivatives are used for many special applications, for example for dye intermediates, heavy duty detergents, agricultural chemicals and pharmaceuticals. Aromatic dianhydrides, in particular, are useful for the manufacture of high performance resins. However, aromatic anhydrides, especially when finely divided, are extremely difficult to handle because they generate relatively large amounts of dust. Dust from aromatic anhydrides can be irritating and TMA dust, in particular, can exert sensitizing effects when inhaled.

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   Since a large part of the exposure to this dust takes place during the handling of solid aromatic anhydrides, a method suitable for removing airborne aromatic anhydride dust is desirable.



   Different techniques have been applied to the removal of dust. For example, MORI describes in US Patent No. 2,222,370 a process for preventing and reducing dust in coal mines by spraying in the coal mining sites a mixture or emulsion of petroleum and water, the water being present in an amount sufficient to render the sprayed oil non-flammable.



   Butcher, described in US Patent No. 2,399,464, an improved liquid spray agent capable of inhibiting surface dusting of soil on playgrounds, exercise grounds and powdery alleys. The stable liquid composition for reducing dust comprises a low-viscosity and low-volatility oil obtained by distillation of petroleum, naphthenic acid, a wetting agent consisting essentially of a sodium salt.
 EMI2.1
 . ". of a higher sulfonated alcohol, water and a germicide.



   Heald et al. describe in US Patent No. 2,423,449 the treatment of soap to reduce dust generation and the tendency to clump by spraying the soap particles with a heavy mineral oil fraction.



   Moen et al. describe in US Patent No. 2,585,026 the reduction in the amount of dust produced by the grain during handling by applying to the grain an emulsion of water and mineral oil.



   Taylor describes in U.S. Patent No. 3,913,637 the use of a liquid material such as white mineral oil to reduce the amount of dust in a concentrated solid masterbatch that is added to animal and poultry feed, the concentrated

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 consisting essentially of gentian violet, which is a selective fungicide inhibitor of "Candida albicans", and inert constituents.



   Ito et al. describe in US Patent No. 4,276,308 the use of an adhesive polybutene in the preparation of pellets containing a carboxylate, the pellets being used with safety as an effective preservative for wood.



   Japanese patent publications Nos. 80037521, 50053538 and 56059701 describe a powdery agent for agricultural use which gives off less dust, this powdery agent for agricultural use being prepared by mixing the active ingredient with an inorganic powder vehicle and polybutene or polyisobutene.



   Darham Jr. et al. describe in U.S. Patent No. 4,208,433 the use of an oilseed vehicle, such as corn oil, unrefined cottonseed oil and soybean oil, to adsorb dust into whole grains for sowing to suppress explosions in grain stores, reduce the risk of fire and improve environmental conditions for workers.



   Li et al. disclose in US Patent No. 4,490,511 a hardener for epoxy resins which is a mixture of anhydride which produces little dust, which mixture comprises a solid anhydride, TMA, and 1 to about 10% by weight of a normally liquid anhydride. The liquid anhydride is chosen from methylhexahydrophthalic anhydride, methylnadic anhydride and dodecylsuccinic anhydride. The TMA flakes can be moistened a priori or else the TMA in fine powder can be moistened a posteriori with the liquid anhydride to give the TMA a very reduced tendency to give off dust.



   The Applicant has now discovered a method for suppressing the dust emitted by solid aromatic anhydrides, which method consists in applying to

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 aromatic anhydride an organic compound which has no appreciable harmful influence on the harmful aromatic anhydride and which is chosen from agents which are not liquid anhydrides.



  Overview of the invention.



   The subject of the invention is a method for removing the dust released by solid aromatic anhydrides, which method comprises the treatment of solid aromatic anhydrides with at least one organic compound, according to which the organic compound is both liquid and substantially non-volatile at normal ambient temperatures and pressures and according to which the organic compound does not contain anhydride functionality. The treatment is carried out by spraying on the solid aromatic anhydride, by mixing the organic compound directly with the solid aromatic anhydride or by application of a solution of the organic compound in a volatile solvent.



   A subject of the invention is also stabilized aromatic anhydride compositions which give off quantities
 EMI4.1
 reduced airborne dust. The .,. compositions include a solid aromatic anhydride and an organic compound, the solid aromatic anhydride being present in an amount in the range of from about 90% by weight to about 99.999% by weight and the organic compound being present in an amount of range from about 0.001% by weight to about 10% by weight, each amount being related to the weight of the composition.



  Description of preferred embodiments.



   Due to the tendency of solid aromatic anhydrides to emit dust and the potential sensitization effects of TMA dust upon inhalation, there is a need for a process suitable for removing dust from solid aromatic anhydrides.



  To this end, a new process has been developed and is the subject of the present invention. The process for removing

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 dust from solid aromatic anhydrides includes treating the aromatic anhydride with an organic compound, whereby the organic compound is both liquid and substantially non-volatile at normal ambient temperatures and pressures. These organic compounds are distinguished by their ability to reduce the amount of airborne dust that is released by aromatic anhydride and by their ability to have no detrimental effect on aromatic anhydride or on the products that are made of it.



   The anhydrides which are of interest according to the invention are aromatic anhydrides which are solid at ordinary ambient temperatures and which comprise the following structure (I) in a part of the anhydride molecule.
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     Ri to R4 can be the same or different and without limitation of the classes in which they can be chosen, Ri to R4 can be hydrogen atoms, alkyl radicals, alkenyl radicals, aromatic radicals, alkyllaromatic radicals, aromatic radicals condensates forming, for example, a naphthalene ring, halo radicals, other anhydride or aromatic anhydride entities or entities containing sulfur, nitrogen or phosphorus. Naphthalene dicarboxylic dianhydride and naphthalenecarboxylic anhydride are examples of ring anhydrides

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 aromatic condensed. Preferably, the aromatic anhydrides have 8 to 40 carbon atoms.



   It should be noted that the main object of the present invention is to provide aromatic anhydride compositions having a reduced tendency to give off harmful dust. Another object of the invention is to provide a process for treating solid aromatic anhydrides using suitable organic compounds to suppress the formation of anhydride dust without adversely affecting the final application of the anhydride. The nature of the aromatic anhydride useful for the purposes of the invention is not limited, except that the anhydride is a solid at ordinary ambient temperatures and that it comprises the structure (I) above in part of its molecule.



   Without limiting the nature of the solid aromatic anhydrides suitable for the compositions and methods of the invention, the particularly preferred anhydrides are phthalic anhydride, trimellitic anhydride, pyromellitic dianhydride and
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 3, 3 ', 4, 4'-biphenyltetracarboxylic dianhydride.



  ./ Structural anhydrides:
 EMI6.2
 where X is chosen from:

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 EMI7.1
 are also particularly preferred anhydrides. They are usually called, respectively, oxybisphthalic anhydride, dianhydridebenzophenonetetracarboxylic, sulfonylbisphthalic anhydride, isopropylidenebisphthalic anhydride and 2,2, bis (3,4-dicarboxyphenyl) hexafluoropropane dianhydride.



   Particularly preferred anhydrides also belong to the category of anhydrides of structure (II) above where X is chosen from:
 EMI7.2
 
 EMI7.3
 z and. r ".. r '.
 EMI7.4
 where Y is H or F and Z is chosen from:
 EMI7.5
 
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 Trimellitic anhydride is one of the solid aromatic anhydrides especially preferred for the compositions and methods of the present invention.

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   A general process for the preparation of aromatic anhydrides is the oxidation of the corresponding methyl-substituted aromatic diet into di- or polycarboxylic acid. The carboxylic acid radicals adjacent to each other on the aromatic ring can be dehydrated to anhydride. Simple heating is usually sufficient for the formation of the anhydride. The methyl radicals can be oxidized to carboxylic acid radicals according to any of a number of known methods, for example oxidation with potassium permanganate or oxidation by air catalyzed by heavy metals.



   Many of the anhydrides mentioned above as the particularly preferred anhydrides of the invention are industrial products. For example, phthalic anhydride and trimellitic anhydride are produced annually in millions of kilograms. The dianhydride 3, 3 ', 4, 4'-diphenyltetracarboxylic is also a commercial anhydride which can be prepared, for example, by oxidation of 3, 3', 4, 4'-tetramethylbiphenyl to tetracarboxylic acid using any one of many oxidizing agents such as potassium permanganate and then by heating for the conversion of tetracarboxylic acid to anhydride with elimination of two molecules of water.

   Alternatively, phthalic acid can be condensed directly to 3, 3 ', 4, 4'-biphenyltetracarboxylic acid. The tetra carboxylic acid can be dehydrated to the dianhydride. See, for example, US Patent No. 4,581,469. Pyromellitic dianhydride and the anhydrides of structure (II) where X is chosen from:
 EMI8.1
 

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 can be prepared by oxidation of the corresponding tetramethyl compound according to any one of many processes for the oxidation of aromatic methyl radicals to carboxylic acid radicals, for example oxidation with potassium permanganate or air oxidation catalyzed by heavy metals. The resulting tetracarboxylic acids are advantageously dehydrated to the corresponding dianhydrides.

   US Patents 3,022,320 and 2,712,543 describe the preparation of sulfonylbisphthalic anhydride and isopropylidene-bisphthalic anhydride, respectively, and British Patent No. 1,019,573 describes a process for preparing oxybisphthalic anhydride. The tetramethylsubstituted feed for the preparation of 2,2-bis (3,4-dicarboxyphenyl) hexafluoropropane and 2,2-bis (3,4dicarboxyphenyl) hexafluoropropane dianhydride can be prepared by condensing the o-xylene with hexafluoroacetone using an acid catalyst. Benzophenonetetracarboxylic dianhydride is sold by Aldrich Chemical Company, Milwaukee, Wisconsin.

   Anhydrides of structure (II) where X is chosen from:
 EMI9.1
 and Z and Y are as defined above, can be prepared, for example, by reacting the corresponding diphenol, such as hydroquinone, with two equivalents of 4-fluorophthalic anhydride during a nucleophilic aromatic substitution reaction . Such a process is described in European patent application No. 0 288 974 and the references cited therein.



   Suitable organic compounds useful in reducing the amount of dust released by solid aromatic anhydrides are the organic compounds which are

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 both liquid and substantially non-volatile at normal ambient temperatures and pressures. The preferred compounds are hydrocarbons, esters, mineral oils, white oils, hydrogenated polybutenes and polybutenes, alcohols and polyalphaolefins. Particularly preferred compounds are white oil, polybutenes and hydrogenated polybutenes, 2-ethylhexanol, trioctyl trimellitate (TOTM) and triisononyl trimellitate.



   The hydrocarbons which are suitable for reducing the amount of dust released by aromatic anhydrides are organic compounds comprising hydrogen and carbon atoms and they can be linear, branched, saturated, unsaturated or aromatic, this possibly in combination. It is preferred that these hydrocarbons are liquid and substantially non-volatile at normal ambient temperatures and pressures. Especially preferred hydrocarbons have 6 to 100 carbon atoms and more preferably 8 to 30 carbon atoms.



   A white oil is a fraction of highly refined lubricating oil with a clear and colorless appearance.



  It is also odorless and tasteless and substantially free of aromatic hydrocarbons, sulfur and nitrogen. It has a Saybolt +30 color and a low absorbance in the ultraviolet. Typical white oils are prepared by catalytic hydrogenation of a lubricating oil fraction that has undergone dewaxing and / or solvent extraction and are used in cosmetics and for certain medical purposes. A typical white oil suitable as a dust suppressant is a white oil 55 which can be purchased from Amoco Oil Company under the designation Amoco White Mineral Oil No. 5-NF. This white oil has a sulfur content of less than 2 ppm (by weight) and a nitrogen content of less than 1 ppm (by weight) and comprises approximately 50% of paraffins and 50% of naphthenes.

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   White oil is a preferred compound of the invention for removing dust from aromatic anhydrides because it is colorless and odorless and does not impart undesirable properties to the treated aromatic anhydride, but to other refined original oils both mineral, animal or vegetable are also suitable as dust suppressants according to the invention. For example, oils selected from cotton, nut, soy, sunflower, rapeseed, sesame, olive, corn, safflower, palm, palm kernel, copra, flax and Castor oil are suitable vegetable oils. Suitable animal oils include beef tallow oil and bacon oil.

   Suitable mineral oils are refined oils of petroleum origin having a viscosity of about 100 mm2 S-l (1 cst) to loo. C at around 10,000 mm2 s (100 cSt) at 100 C.



   Other organic compounds suitable for removing dust from aromatic anhydrides are viscous polybutenes having a number average molecular weight of about 250 to about 500 and a viscosity at 380C.
 EMI11.1
 (1000F) from about 400 to about 110,000 mm2 s' (4 to. ".



  1,100 cSt). These polybutenes are essentially clear like water, resistant to oxidation under the effects of heat and light, non-drying and thermally decomposable without residue at a temperature above about 275 C. These polybutenes can be obtained by polymerization of '' a stream of refinery butenes in the presence of a Friedel and Crafts type catalyst. The refinery butene stream, often called "C" or "BB" (butane-butene) olefin streams produced in petrochemical cracking units, is a convenient source of isobutylene, 1-butene, cis -2-butene and trans-2-butene. The polybutenes include isobutylene-butene copolymers consisting of high molecular weight monoolefins (95 to 100%) and isoparaffins.

   Polybutenes suitable as dust suppressants are

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 available on the market. Typical examples of suitable polybutenes are Indopol L-4, Indopol L-10, Indopol L-14, Indopol L-50 and Indopol L-100 sold by Amoco Chemical Company.



   In addition, hydrogenated polybutenes are suitable as dust suppressants for aromatic anhydrides. The hydrogenated polybutenes are marketed. For example, they can be obtained from Amoco Chemical Company under the designation Panalane.



  These hydrogenated polybutenes are prepared by hydrogenating, for example, the aforementioned viscous polybutenes so as to hydrogenate all or most of the unsaturations of polybutene.



   The polyalphaolefins obtained by dimerization, trimerization or oligomerization of alphaolefins, such as C6 to C2 alphaolefins, wells by hydrogenation for the removal of unsaturations, are also hydrocarbons of the invention which are suitable for removing dust from aromatic anhydrides. These polyalphaolefins are available in a wide variety of viscosities and molecular weights, but are all distinguished by the excellence of their chemical inertness and their viscosity properties. They find wide application as synthetic lubricants. They are liquid and substantially non-volatile under normal ambient conditions. They are marketed, for example, by the Gulf Chemical Company.

   The polyalphaolefins obtained by dimerization and trimerization of a C10 alphaolefin are compounds which are particularly suitable for removing dust from aromatic anhydrides.



   Alcohols and alcohol mixtures are also useful compounds for suppressing the formation of dust by aromatic anhydrides. To be effective, alcohol must be both liquid and substantially non-volatile at normal ambient temperatures and pressures. An alcohol

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 liquid is easier to apply on aromatic anhydride and can also have a coating effect to prevent dust generation. Suitable alcohols are monohydroxylated alcohols having 6 or more carbon atoms and preferably 6 to 30 carbon atoms and they may be linear, branched, cyclic, heterocyclic or aromatic.

   Examples of alcohols in this category, without intending to limit the nature of the alcohols useful for the purposes of the invention, are hexanols, for example l-hexanol, 2-hexanol and cyclohexanol; heptanols; octanols, for example 2-ethylhexanol, isooctanol and 1-octanol; and isononyl alcohol. Diols such as ethylene glycol or propylene glycol are also suitable alcohols. These diols are liquid and substantially non-volatile at normal ambient temperatures and pressures. Other diols having 3 or more carbon atoms and preferably 3 to 30 carbon atoms are also suitable. Alcohols having three or more hydroxyl radicals are also suitable alcohols, for example glycerol and alcohols called polyols.

   These polyhydroxy compounds preferably have 3 to 6 hydroxyl radicals and 3 to 30 carbon atoms. A particularly preferred alcohol is 2-ethylhexanol because it is widely used to prepare esters with anhydride or trimellitic acid. It is marketed by the companies Eastman Chemicals, Ashland Chemical, Shell Chemical and Union Carbide. Nonyl alcohol, also called isononyl alcohol, is also particularly preferred. It is marketed by the Exxon Chemical Company.



   Esters and ester mixtures are also useful organic compounds for reducing the amount of dust released by aromatic anhydrides. The esters which are useful are those which are liquid and substantially non-volatile at normal ambient temperatures and pressures. Particularly suitable esters are those

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 derived from mono-, di- and polycarboxylic aromatic acids. Esters from aliphatic carboxylic acids are also useful. These acids can be mono-, di- or polycarboxylic. They can be linear, branched, cyclic, saturated or unsaturated. Adipic acid and oleic acid are examples of these acids. These acids preferably have 1 to 30 carbon atoms.



   The particularly preferred esters useful for suppressing the dust of aromatic anhydrides are the esters derived from acids chosen from terephthalic acid, isophthalic acid, phthalic acid, trimellitic acid, pyromellitic acid, a naphthalenecarboxylic acid, naphthalenedicarboxylic acid, oleic acid and adipic acid.



   The esters of solid aromatic anhydrides forming dust are also organic compounds suitable for suppressing anhydride dust. For example, a suitable dust suppressant for the benzophenonetetracarboxylic dianhydride is an ester of benzophenonetetracarboxylic acid. So the esters of
 EMI14.1
 acids resulting from the hydrolysis of aromatic anhydrides.,. Particularly preferred above mentioned are suitable as organic compounds for suppressing dust from aromatic anhydrides.



   The organic esters of the invention are prepared by esterifying the acids with an alcohol. The alcohol can be any alcohol. Suitable alcohols, without limitation of the nature of the alcohol, are, for example, methanol, ethanol, propanols, butanols, 2-ethylhexanol, isooctanol, glycols, polyols or mixtures of these alcohols or others. The alcohols can be linear, branched, cyclic or aromatic. The preferred alcohols, glycols and polyols used to prepare these esters have 1 to 30 carbon atoms. 2-Ethylhexanol and isononyl alcohol are particularly preferred alcohols.

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   Trioctyl trimellitate (TOTM) prepared by esterification of trimellitic acid or trimellitic anhydride with 2-ethylhexanol is a particularly preferred ester to reduce dust generation by aromatic anhydrides. Triisononyl trimellitate, prepared by esterification of trimellitic anhydride with isononyl alcohol, is also a particularly preferred ester for reducing the formation of dust by aromatic anhydrides.



   For the purposes of the present invention, normal ambient temperatures and pressures are the atmospheric conditions normally observed in the open air or in a sheltered room, for example in a chemical or other plant. In a preferred embodiment of the invention, the organic compound must be liquid when applied to the aromatic anhydride and it must remain liquid. This facilitates the application and removal of dust, respectively. However, it is not absolutely required that the organic compound envisaged according to the invention be liquid at ambient temperatures and pressures. It can also be a solid and can be heated or dissolved in a solvent to facilitate application to the aromatic anhydride.

   In addition, it is not required that the organic compounds of the invention exist in liquid form throughout the range of normal ambient temperatures and pressures. The organic compounds of the invention useful for suppressing dust from aromatic anhydrides can be liquids in only part of the range of normal ambient temperatures and pressures.



   In one embodiment, the organic compound selected as the dust suppressant for aromatic anhydride is a compound which is liquid at normal ambient temperatures and pressures, but which is volatile at a temperature selected for the purpose of carrying out the anhydride at a later stage of manufacture.

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  In this embodiment, the organic compound acts as a dust suppressant during the handling of the aromatic anhydride, but it is eliminated in substance or completely during the manufacturing stage where the aromatic anhydride is incorporated into a product. For example, when a dianhydride is used to prepare a polyimide, it is possible to choose a dust suppressor which is non-volatile at normal ambient temperatures and pressures, but which is volatile at the temperature chosen for the condensation of the dianhydride with the amine. to produce the polyimide, so that the dust suppressant is removed from the final product.



   According to the process of the invention, the aromatic anhydride is brought into contact with the organic compound so that the surface of the aromatic anhydride is coated with the organic compound. As a rule, solid aromatic anhydride is present in the form of powder, flakes, crystals, briquettes, granules or pellets.



   The organic compound can be applied to
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 aromatic anhydride in at least one of three ways. Preferably, the aromatic anhydride is brought into contact with the organic compound by spraying the latter onto the surface of the aromatic anhydride. Alternatively, stirring can be maintained and the organic compound is mixed directly by stirring with the solid aromatic anhydride. Third, a diluent is added to the organic compound to ensure more uniform application of it. The mixture of the organic compound and the diluent is applied by spraying or by direct agitation. The diluent is then removed. A suitable diluent can be any volatile solvent miscible with the organic compound.



   The treatment must be such as to apply a quantity of aromatic compound to the surface of the aromatic anhydride in the range of approximately 10 ppm.

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 by weight (0.001% by weight) to about 100,000 ppm by weight (10% by weight), preferably in the range of about 50 ppm by weight (0.005% by weight) to about 20,000 ppm by weight (2% by weight) and preferably in the range of about 100 ppm by weight (0.01% by weight) to about 2000 ppm by weight (0.2% by weight), based on the weight of the aromatic anhydride treated.



   A subject of the invention is also stabilized aromatic anhydride compositions having a reduced tendency to give off dust, which compositions comprise the solid aromatic anhydride treated with at least one organic compound which is both liquid and substantially non-volatile at normal ambient temperatures and pressures, the solid aromatic anhydride being present in an amount in the range of about 90% by weight to about 99.999% by weight, based on the total weight of the composition, and the compound organic being present in an amount in the range of about 0.001% by weight to about 10% by weight, based on the total weight of the composition.

   These compositions are advantageously prepared by the process of the present invention.
 EMI17.1
 ..?
The following examples are given to facilitate a better understanding of the methods and compositions of the invention and to illustrate it without limiting its scope.



  EXAMPLE 1. -
A qualitative test is performed to demonstrate the effectiveness of the process of the present invention.



   An untreated TMA flake sample, or sample # 1, is stirred by churning for 1 hour at 90-120 rpm in a stainless steel mixing jar with internal deflectors. The churned TMA is collected and introduced into a transparent glass jar allowing the contents of the jar to be clearly observed.



   500 ppm of white oil are added to a second TMA sample, or sample no. 2.

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 the nO 2 sample by churning under the same conditions as the nO 1 sample. The two TMA samples are visually compared with respect to the amount of TMA dust released into the air when these samples are agitated in their jar open under a hood. It is observed that dust is released from the untreated sample or sample nO 1. On the other hand, a relatively very small amount of TMA dust escapes from the jar containing the treated TMA sample or sample n 2.



  EXAMPLE 2.-
Various tests are performed to determine the amount of airborne TMA dust that could form when a selected TMA sample is stirred. The experimental system includes a stirring generator to shake the TMA sample and a collecting device to collect the TMA dust carried by the air. The stirring generator is a sieve shaker used to disperse dust in
 EMI18.1
 air when the TMA sample is shaken. When it is dispersed in the air, the TMA dust is * collected using the collecting device which consists of a small portable vacuum pump connected to a cassette of Millipore aerosol filters matched according to their weight.

   The filter cassette matched according to their weight comprises a set of two filters of equal weight arranged in series. The filters of the same cassette are manufactured so that their weight difference is 0, 0001 g. TMA dust collects on the first filter and the weight difference between the first filter and the second gives the amount of TMA dust collected on the first filter.



   Each test is carried out as follows. The TMA sample (100 g) is introduced into a 480 ml (16 ounce) jar with an 89 mm lid. The jar is stirred using the sieve shaker and collected for

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 1 hour TMA dust carried by the air. The vacuum pump setting is 1.2 liters per minute. All weighings are made on an analytical laboratory balance. Samples 3, 4 and 5 are blank controls (air samples), that is, the jar does not contain TMA. Samples 6 and 7 are untreated TMA. Samples 8 and 9 are TMA treated with 1000 ppm white oil and samples 10 and 11 are TMA treated with 1000 ppm trioctyl trimellitate (TOTM).



   The results of these tests are presented below in Table I.



   TABLE I
TMA dust removal
 EMI19.1
 
 <tb>
 <tb> Echan-Description <SEP> from <SEP> Weight, <SEP> g
 <tb> furrow <SEP> the sample <SEP> 1st <SEP> 2nd <SEP> A <SEP> weight
 <tb> no <SEP> filter <SEP> filter
 <tb> 3 <SEP> air <SEP> 0.0443 <SEP> 0, <SEP> 0443 <SEP> 0, <SEP> 0000
 <tb> 4 <SEP> air <SEP> 0.0452 <SEP> 0.0451 <SEP> 0.0001
 <tb>.,.
 <tb>



  5 <SEP> air <SEP> 0.0450 <SEP> 0, <SEP> 0450 <SEP> 0, <SEP> 0000
 <tb> 6 <SEP> TMA <SEP> 0.0486 <SEP> 0.0450 <SEP> 0.0036
 <tb> 7 <SEP> TMA <SEP> 0.0475 <SEP> 0, <SEP> 0450 <SEP> 0.0025
 <tb> 8 <SEP> TMA <SEP> + <SEP> oil <SEP> white
 <tb> (1 <SEP> 000 <SEP> ppm) <SEP> 0.0519 <SEP> 0.0512 <SEP> 0.0007
 <tb> 9 <SEP> TMA <SEP> + <SEP> oil <SEP> white
 <tb> (1 <SEP> 000 <SEP> ppm) <SEP> 0.0488 <SEP> 0.0487 <SEP> 0.0001
 <tb> 10 <SEP> TMA <SEP> + <SEP> TOTM
 <tb> (1 <SEP> 000 <SEP> ppm) <SEP> 0.0515 <SEP> 0.0509 <SEP> 0.0006
 <tb> 11 <SEP> TMA <SEP> + <SEP> TOTM
 <tb> (1 <SEP> 000 <SEP> ppm) <SEP> 0.0447 <SEP> 0, <SEP> 0452-0, <SEP> 0005
 <tb>
 

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The tests carried out with the air samples, that is to say samples Nos 3,4 and 5,

   demonstrate that there is no weight gain when the sample consists of air. this indicates that ambient dust is negligible for the execution of the test and that only TMA dust is collected when the TMA samples are tested. Both white oil and TOTM reduce or remove dust from TMA.



  EXAMPLE 3.-
A series of tests is carried out to confirm the results of those carried out in Example 1 and to minimize the effects of experimental and instrumental errors. For these tests, 125 g samples are used, the sampling time being increased to 5 hours and the vacuum setting being maintained at 2.8 liters per minute. In addition, the amounts of material added to suppress dust are changed. The experimental system is the same as that for the tests carried out in Example 2.



   The results of these tests are presented in Table II below.

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   TABLE II Suppression of TMA1 dust
 EMI21.1
 
 <tb>
 <tb> Echan-Treatment <SEP> Weight, <SEP> a
 <tb> furrow <SEP> Agent <SEP> Quantity <SEP> 1st <SEP> 2nd <SEP> Dust
 <tb> n <SEP> e <SEP> ppm <SEP> filter <SEP> filter <SEP> from <SEP> TMA
 <tb> 12--0, <SEP> 1595 <SEP> 0.0445 <SEP> 0.1150
 <tb> 13 <SEP> TOTM <SEP> 100 <SEP> 0.0518 <SEP> 0.0438 <SEP> 0.0080
 <tb> 14 <SEP> TOTM <SEP> 250 <SEP> 0.0568 <SEP> 0.0452 <SEP> 0.0116
 <tb> 15 <SEP> TOTM <SEP> 500 <SEP> 0.0546 <SEP> 0.0457 <SEP> 0.0089
 <tb> 16 <SEP> TOTM <SEP> 750 <SEP> 0.0464 <SEP> 0.0447 <SEP> 0.0017
 <tb> 17 <SEP> TOTM <SEP> 1000 <SEP> 0.0488 <SEP> 0.0447 <SEP> 0.0041
 <tb> 18--0, <SEP> 0846 <SEP> 0.0445 <SEP> 0, <SEP> 0401
 <tb> 19 <SEP> Oil2 <SEP> 100 <SEP> 0.0464 <SEP> 0, <SEP> 0443 <SEP> 0.0021
 <tb> 20 <SEP> Oil <SEP> 250 <SEP> 0.0456 <SEP> 0.0449 <SEP> 0.0007
 <tb> 21 <SEP> Oil2 <SEP> 750 <SEP> 0,

  0488 <SEP> 0.0482 <SEP> 0.0006
 <tb> 22 <SEP> Oil2 <SEP> 1000 <SEP> 0.0461 <SEP> 0.0457 <SEP> 0.0004
 <tb> 23 <SEP> p3 <SEP> 1000 <SEP> 0.0458 <SEP> 0.0451 <SEP> 0.0007
 <tb>
 For a 125 g sample and a vacuum setting of 2.8 liters per minute with a test time of 5 hours.



  2 White oil.



    3p Panalane (hydrogenated polybutenes).



   These data indicate that as the amount of dust suppressant increases, the amount of dust detected decreases. In addition, these results show that white oil has a better ability to suppress dust than TOTM.



  EXAMPLE 4.-
These tests are carried out to determine whether the process according to the invention for removing dust can hinder the final applications of TMA. Untreated TMA and treated TMA are esterified with 2-ethylhexanol

  <Desc / Clms Page number 22>

 with white oil or TOTM. The coloration of each of the esterification products is evaluated by measuring the coloration of the crude ester and that of the final ester on the APHA color scale. The coloration of the TMA is measured by the spectrophotometric method known as the AE method for TMA, according to which the difference in total coloration is determined between a solution of 3N NaOH and a solution of 5 g of TMA in 30 ml of 3N NaOH. The value of AE as measured with a spectrophotometer depends on the coloring of the TMA at wavelengths from 400 to 700 nm.



   The results of these colorimetric measurements are presented in Table III below.



   TABLE III
Applications after removal of TMA dust
 EMI22.1
 
 <tb>
 <tb> Echan-Treatment <SEP> Time <SEP> from <SEP> AE <SEP> CEF <SEP> CEB
 <tb> furrow <SEP> cooking
 <tb> no <SEP> h
 <tb> 24-5 <SEP> 2, <SEP> 43. <SEP> 30 <SEP> 45
 <tb> 25 <SEP> 0, <SEP> 1% <SEP> p <SEP> oil3 <SEP> 4-30 <SEP> 45
 <tb> 26 <SEP> 0.1% <SEP> p <SEP> TOTM <SEP> 4, <SEP> 75-30 <SEP> 45
 <tb>
 
 EMI22.2
 1 CEF - Coloring of the final ester.



  2 CEB - Coloring of the crude ester.



    3 - White oil.



   These data show that neither the white oil nor the TOTM give rise to disadvantages by coloring during the esterifications of TMA with 2-ethylhexanol. The sample treated with white oil and that treated with TOTM did not lead to any observable difference in the coloration of the crude ester or the coloration of the final ester, in comparison with the sample of untreated TMA. The coloration of the crude ester is that of the crude esterification mixture. The

  <Desc / Clms Page number 23>

 coloring of the final ester is that of the ester after treatment with 1% of activated charcoal and training of the alcohol in order to remove the excess of the alcohol used for the esterification.



  EXAMPLE 5.-
Additional tests are performed to determine if the dust suppressant can adversely affect TMA end applications. These tests are carried out according to the procedure described in Example 4 above, with the difference that 10,000 ppm of white oil or 10,000 ppm of TOTM are used, on a weight basis.



   The results of the colorimetric measurements are presented in Table IV below.



   TABLE IV
Applications after removal of TMA dust
 EMI23.1
 
 <tb>
 <tb> Echan-Treatment <SEP> Time <SEP> from <SEP> AE <SEP> CEF <SEP> CEB
 <tb> furrow <SEP> cooking
 <tb> na <SEP> h
 <tb> J-
 <tb> 27-4, <SEP> 5 <SEP> 3.03 <SEP> 35 <SEP> 40
 <tb> 28 <SEP> 1% <SEP> p <SEP> oil3 <SEP> 4.5 <SEP> 3.02 <SEP> 30 <SEP> 45
 <tb> 29 <SEP> 1% <SEP> p <SEP> TOTM <SEP> 4.0 <SEP> 3.08 <SEP> 35 <SEP> 45
 <tb>
 1 CEF-Coloring of the final ester.



  2 CEB-Coloring of the crude ester.



  3-White oil.



   Again, neither the white oil nor the TOTM give rise to disadvantages by coloring during the esterifications of TMA with 2-ethylhexanol.



  EXAMPLE 6.-
The trimellitic esters mentioned in Table III are used as plasticizers to make clear poly (vinyl chloride) (PVC) sheets. The leaves are subjected to various tests to determine whether the

  <Desc / Clms Page number 24>

 0.1% TOTM or 0.1% white oil added to the TMA can lead to poor performance of the final products.



   The results of the performance tests detailed in Table V show that these agents do not induce insufficient performance in the PVC sheets. The results of the performance tests are equivalent for the treated TMA and the untreated TMA. Performance tests include tensile properties, volatility on activated carbon, extraction with soapy water, extraction with mineral oil, compatibility with humidity, seepage-exudation with roller, hardness Shore A and the brittleness temperature.

  <Desc / Clms Page number 25>

 



   TABLE V
Evaluation of the performance of clear poly (vinyl chloride) sheets added as a TOTM plasticizer made of TMA treated with white oil or TOTM
 EMI25.1
 
 <tb>
 <tb> Processing <SEP> from <SEP> TMA
 <tb> (N <SEP> from <SEP> the sample <SEP> from <SEP> TOTM)
 <tb> None <SEP> 0.1% <SEP> oil <SEP> 0, <SEP> 1% <SEP> TOTM
 <tb> (24) <SEP> (25) <SEP> (26)
 <tb> Properties <SEP> from <SEP> traction
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 23.353 <SEP> 22,898 <SEP> 22,885
 <tb> (PSI) <SEP> (3387) <SEP> (3321) <SEP> (3319)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 15,548 <SEP> 16,010 <SEP> 15,410
 <tb> (PSI) <SEP> (2255) <SEP> (2322) <SEP> (2235)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 22,023 <SEP> 21,926 <SEP> 20.954
 <tb> (PSI) <SEP> (3194) <SEP> (3180) <SEP> (3039)

  
 <tb> Elongation <SEP>% <SEP> 349 <SEP> 351 <SEP> 347
 <tb> Volatility <SEP> on <SEP> carbon <SEP> activated-Loss <SEP> from <SEP> weight <SEP>% <SEP> (90 C)
 <tb> 24 <SEP> hours <SEP> 0.5 <SEP> 0.5 <SEP> 0.5
 <tb> 48 <SEP> hours <SEP> 0.6 <SEP> 0.6 <SEP> 0.6
 <tb> Extraction <SEP> by <SEP> water <SEP> soapy-Loss <SEP> from <SEP> weight <SEP>% <SEP> (90 C)
 <tb> 48 <SEP> hours <SEP> 0.2 <SEP> 0.2 <SEP> 0.2
 <tb> 72 <SEP> hours <SEP> 0.2 <SEP> 0.2 <SEP> 0.2
 <tb> Extraction <SEP> by <SEP> oil <SEP> mineral-Loss <SEP> from <SEP> weight <SEP>% <SEP> 70 C)
 <tb> 24 <SEP> hours <SEP> 2.4 <SEP> 2.3 <SEP> 2.3
 <tb> Compatibility <SEP> with <SEP> humidity <SEP> - <SEP> Exudation <SEP> (900C)
 <tb> 7 <SEP> days <SEP> none <SEP> none <SEP> none
 <tb> Oozing-Exudation <SEP> to <SEP> roller <SEP> (temperature <SEP> ambient)

  
 <tb> 96 <SEP> hours <SEP> none <SEP> none <SEP> none
 <tb> Hardness <SEP> Shore <SEP> A
 <tb> Initial <SEP> 94 <SEP> 94 <SEP> 93
 <tb> 10 <SEP> seconds <SEP> 89 <SEP> 89 <SEP> 88
 <tb> Temperature <SEP> from <SEP> fragility
 <tb> Degrees <SEP> C-22-24, <SEP> 9-22, <SEP> 8
 <tb>
 

  <Desc / Clms Page number 26>

 EXAMPLE 7.-
The trimellitic esters described in Table III are used to make up poly (vinyl chloride) UL 1050C for insulating sheaths of electric wires.



  These various PVCs are evaluated according to different test techniques to determine whether the addition of 0.1% TOTM or 0.1% white oil to the TMA causes performance difficulties with the final products.



   The results of the performance tests, given in Table VI, show that these additives do not give rise to performance difficulties in PVC insulating sheaths for electrical wires containing a plasticizer made of treated TMA. The performance tests include measurements of the initial tensile strength, measurements of the tensile strength after 7 days at 1360C and the percentage of retention of the tensile strength after the treatment of 7 days.

  <Desc / Clms Page number 27>

 



   TABLE VI Evaluation of the performance of insulating sheaths of electric wires containing TOTM plasticizer made from TMA treated with white oil or TOTM as dust suppressor
 EMI27.1
 
 <tb>
 <tb> Processing <SEP> from <SEP> TMA
 <tb> (NI <SEP> from <SEP> the sample <SEP> from <SEP> TOTM)
 <tb> None <SEP> 0.1% <SEP> oil <SEP> 0, <SEP> 1% <SEP> TOTM
 <tb> (24) <SEP> (25) <SEP> (26)
 <tb> Properties <SEP> from <SEP> traction
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 23.608 <SEP> 23,471 <SEP> 22, <SEP> 885
 <tb> (PSI) <SEP> (3424) <SEP> (3404) <SEP> (3319)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 16,258 <SEP> 16,031 <SEP> 16,148
 <tb> (PSI) <SEP> (2358) <SEP> (2325) <SEP> (2342)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 21,487 <SEP> 21,368 <SEP> 20,685
 <tb> (PSI) <SEP> (3109) <SEP> (3099) <SEP> (3000)

  
 <tb> Elongation <SEP>% <SEP> 363 <SEP> 363 <SEP> 353
 <tb> Aging <SEP> from <SEP> 7 <SEP> days <SEP> to <SEP> 136 C
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 24,794 <SEP> 24,436 <SEP> 23,864
 <tb> (PSI) <SEP> (3596) <SEP> (3544) <SEP> (3461)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 18,499 <SEP> 19, <SEP> 196 <SEP> 18, <SEP> 699
 <tb> (PSI) <SEP> (2683) <SEP> (2784) <SEP> (2712)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 22,857 <SEP> 23,712 <SEP> 23.002
 <tb> (PSI) <SEP> (3315) <SEP> (3439) <SEP> (3336)

  
 <tb> Elongation <SEP>% <SEP> 348 <SEP> 330 <SEP> 321
 <tb> Percentage <SEP> from <SEP> retention
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> 105 <SEP> 104 <SEP> 104
 <tb> Module <SEP> to <SEP> 100% <SEP> 114 <SEP> 119 <SEP> 116
 <tb> Module <SEP> to <SEP> 300% <SEP> 107 <SEP> 111 <SEP> 111
 <tb> Elongation <SEP>% <SEP> 96 <SEP> 91 <SEP> 91
 <tb>
 EXAMPLE 8.-
The trimellitic esters described in Table IV are used as plasticizers to make clear poly (vinyl chloride) (PVC) sheets. These sheets are subjected to evaluation according to different test techniques to determine whether the contribution of 1.0% of TOTM or 1.0%

  <Desc / Clms Page number 28>

 white oil with TMA would cause performance difficulties with the final product.

   An intake of 1% (10,000 ppm) of TOTM or white oil is a really high intake for treatment and if performance difficulties were to appear, they would be very apparent with these high intakes.



   The performance data in Table VII shows that the poly (vinyl chloride) sheets containing the plasticizer made of TMA treated with 1% TOTM or 1% white oil are substantially equivalent to the comparison sheets whose plasticizer is prepared with TMA free of TOTM or white oil.

  <Desc / Clms Page number 29>

 



    TABLE VII
Evaluation of the performance of clear poly (vinyl chloride) sheets added as a TOTM plasticizer made of TMA treated with white oil or
TOTM as a dust suppressor
 EMI29.1
 
 <tb>
 <tb> Processing <SEP> from <SEP> TMA
 <tb> (NO <SEP> from <SEP> the sample <SEP> from <SEP> TOTM)
 <tb> None <SEP> 0.1% <SEP> oil <SEP> 0, <SEP> 1% <SEP> TOTM
 <tb> (27) <SEP> (28) <SEP> (29)
 <tb> Properties <SEP> from <SEP> traction
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 23,698 <SEP> 24, <SEP> 484 <SEP> 23,615
 <tb> (PSI) <SEP> (3437) <SEP> (3551) <SEP> (3425)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 15.521 <SEP> 16,534 <SEP> 15,686
 <tb> (PSI) <SEP> (2251) <SEP> (2398) <SEP> (2275)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 21,223 <SEP> 22,126 <SEP> 21,

  078
 <tb> (PSI) <SEP> (3078) <SEP> (3209) <SEP> (3057)
 <tb> Elongation <SEP>% <SEP> 375 <SEP> 365 <SEP> 375
 <tb> Volatility <SEP> on <SEP> carbon <SEP> activated-Loss <SEP> from <SEP> weight <SEP>% <SEP> (900C)
 <tb> 24 <SEP> hours <SEP> 0.6 <SEP> 0.7 <SEP> 0, <SEP> 5
 <tb> 48 <SEP> hours <SEP> 0.6 <SEP> 0.9 <SEP> 0.6
 <tb> Extraction <SEP> by <SEP> water <SEP> soapy-Loss <SEP> from <SEP> weight <SEP>% <SEP> (900C)
 <tb> '
 <tb> 48 <SEP> hours <SEP> 0.2 <SEP> 0.5 <SEP> 0.2
 <tb> 72 <SEP> hours <SEP> 0.3 <SEP> 0.5 <SEP> 0.3
 <tb> Extraction <SEP> by <SEP> oil <SEP> mineral-Loss <SEP> from <SEP> weight <SEP>% <SEP> (70 C)
 <tb> 24 <SEP> hours <SEP> 2.5 <SEP> 2.1 <SEP> 2.5
 <tb> Compatibility <SEP> with <SEP> humidity <SEP> - <SEP> Exudation <SEP> (900C)

  
 <tb> 7 <SEP> days <SEP> none <SEP> none <SEP> none
 <tb> Oozing-Exudation <SEP> to <SEP> roller <SEP> (temperature <SEP> ambient)
 <tb> 96 <SEP> hours <SEP> none <SEP> none <SEP> none
 <tb> Hardness <SEP> Shore <SEP> A
 <tb> Initial <SEP> 95 <SEP> 95 <SEP> 95
 <tb> 10 <SEP> seconds <SEP> 91 <SEP> 91 <SEP> 92
 <tb> Temperature <SEP> from <SEP> fragility
 <tb> Degrees <SEP> C-24, <SEP> 2-22, <SEP> 8-23, <SEP> 6
 <tb>
 

  <Desc / Clms Page number 30>

 EXAMPLE 9.-
The trimellitic esters described in Table IV are used to make up poly (vinyl chloride) UL 1050C for insulating sheaths of electric wires.



  These various PVCs are evaluated according to different test techniques to determine whether the addition of 1.0% TOTM or 1.0% white oil to the TMA causes performance difficulties with the final products. An intake of 1% (10,000 ppm) of TOTM or white oil is a relatively high intake for treatment and if performance difficulties should arise, they would be very apparent with these higher intakes.



   The results of the performance tests in Table VIII demonstrate that the poly (vinyl chloride) composition used for insulating sheaths of electric wires with a plasticizer made of TMA treated with 1% TOTM or 1% white oil is essentially equivalent to the comparison product made up with TOTM prepared from untreated TMA.

  <Desc / Clms Page number 31>

 



    TABLE VIII Evaluation of the performance of insulating sheaths of electrical wires containing TOTM plasticizer made from TMA treated with white oil or TOTM as a dust suppressor
 EMI31.1
 
 <tb>
 <tb> Processing <SEP> from <SEP> TMA
 <tb> (NO <SEP> from <SEP> the sample <SEP> from <SEP> TOTM)
 <tb> None <SEP> 0.1% <SEP> oil <SEP> 0, <SEP> 1% <SEP> TOTM
 <tb> (27) <SEP> (28) <SEP> (29)
 <tb> Properties <SEP> from <SEP> traction
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 23,471 <SEP> 25,291 <SEP> 23,526
 <tb> (PSI) <SEP> (3404) <SEP> (3668) <SEP> (3412)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 16.603 <SEP> 17,893 <SEP> 16,555
 <tb> (PSI) <SEP> (2408) <SEP> (2595) <SEP> (2401)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 22,498 <SEP> 23,338 <SEP> 22,278
 <tb> (PSI) <SEP> (3263)

    <SEP> (3392) <SEP> (3231)
 <tb> Elongation <SEP>% <SEP> 345 <SEP> 347 <SEP> 354
 <tb> Aging <SEP> from <SEP> 7 <SEP> days <SEP> to <SEP> 136 C
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> MPa <SEP> 25,291 <SEP> 26,042 <SEP> 25,063
 <tb> (PSI) <SEP> (3668) <SEP> (3777) <SEP> (3635)
 <tb> Module <SEP> to <SEP> 100% <SEP> MPa <SEP> 19,713 <SEP> 20, <SEP> 499 <SEP> 19.644
 <tb> (PSI) <SEP> (2859) <SEP> (2973) <SEP> (2849)
 <tb> Module <SEP> to <SEP> 300% <SEP> MPa <SEP> 23, <SEP> 691 <SEP> 24,250 <SEP> 23,933
 <tb> (PSI) <SEP> (3436) <SEP> (3517) <SEP> (3471)

  
 <tb> Elongation <SEP>% <SEP> 340 <SEP> 335 <SEP> 333
 <tb> Percentage <SEP> from <SEP> retention
 <tb> Resistance <SEP> to <SEP> the
 <tb> traction <SEP> 107 <SEP> 103 <SEP> 106
 <tb> Module <SEP> to <SEP> 100% <SEP> 119 <SEP> 115 <SEP> 118
 <tb> Module <SEP> to <SEP> 300% <SEP> 106 <SEP> 104 <SEP> 107
 <tb> Elongation <SEP>% <SEP> 98 <SEP> 96 <SEP> 94
 <tb>
 EXAMPLE 10.-
TMA treated with 0.1% (1000 ppm) TOTM and 0.1% white oil is also used to prepare alkyd and polyester resins based on water used as coatings. No defects, for example "fish eyes", craters or loss of luster, are observed in

  <Desc / Clms Page number 32>

 the layers applied or differences in the physical performance of the coatings formed with the treated TMA, in comparison with the coatings formed with the untreated TMA.

   These evaluations prove that the TMA treated with the organic compounds of the invention is acceptable for the preparation of water-based coatings, which constitutes an important application of TMA.
 EMI32.1
 EXAMPLE 11. -
According to the procedure described in Example 2, 125 g of untreated phthalic anhydride flakes are introduced into a 480 ml jar fitted with a stopper which is stirred with the sieve shaker. The contents of the jar are sampled for 5 hours while maintaining the vacuum setting at 4 liters per minute. During these 5 hours, 80.6 mg of phthalic anhydride dust is collected. During a repetition of the experiment with 125 g of phthalic anhydride treated with 1000 ppm of white oil, 0.6 mg of phthalic anhydride dust is collected on the filters during the 5 hours.



  These results show that the application of white oil leads to a strong reduction in the amount of dust.
 EMI32.2
 ..,. of phthalic anhydride released into the air.



  EXAMPLE 12.-
According to the procedure of Example 11, 125 g of crystals of pyromellitic dianhydride are stirred for 5 hours. During this time, 44.2 mg of pyromellitic dianhydride dust is collected on the filter. During a repetition of the experiment with 125 g of pyromellitic dianhydride treated with 1000 ppm of white oil, only 1.0 mg of airborne pyromellitic dianhydride dust is collected on the filter.



  These results show that the application of white oil as a dust suppressant leads to a large reduction in the amount of pyromellitic dianhydride dust released into the air.


    

Claims (1)

 EMI33.1   CLAIMS CLAIMS 1. - aromatic anhydride composition having a reduced tendency to give off dust, characterized in that it comprises a solid aromatic anhydride treated using an organic compound, in which the organic compound is applied to the surface of the solid aromatic anhydride, in which the aromatic anhydride is a solid at normal ambient temperatures and the organic compound is both liquid and substantially non-volatile at normal ambient temperatures and pressures and in which the organic compound contains no functionality anhydride, the aromatic anhydride being present in an amount in the range of from about 90% by weight to about 99.999% by weight, based on the total weight of the composition,  and the organic compound being present in an amount in the range of about 0.001% by weight to about 10% by weight, based on the total weight of the composition.  2. Composition according to Claim 1, characterized in that the aromatic anhydride is present  EMI33.2  in an amount in the range of about 98% by weight to. 1- about 99.995% by weight, based on the weight of the composition, and the organic compound is present in an amount in the range of about 0.005% by weight to about 2% by weight, based on the weight of the composition.  3. Composition according to Claim 1, characterized in that the aromatic anhydride is present in an amount in the range of approximately 99.8% by weight to approximately 99.99% by weight, based on the weight of the composition, and the organic compound is present in an amount in the range of about 0.01% by weight to about 0.2% by weight, based on the weight of the composition.  4. A composition according to any one of the preceding claims, characterized in that the organic compound is a hydrocarbon.  5.- Composition according to any one of  <Desc / Clms Page number 34>  Claims 1 to 3, characterized in that the organic compound is chosen from the class formed by an ester, a mineral oil, a white oil, a polybutene, a hydrogenated polybutene, an alcohol, a polyalphaolefin, a vegetable oil and an animal oil .  6. Composition according to Claim 5, characterized in that the organic compound is an ester of an acid chosen from the class formed by terephthalic acid, isophthalic acid, phthalic acid, trimellitic acid, l adipic acid and oleic acid.  7. Composition according to any one of Claims 1 to 6, characterized in that the anhydride is chosen from the class formed by trimellitic anhydride, phthalic anhydride, pyromellitic dianhydride, 3, 3 'dianhydride, 4, 4'-biphenyltetracarboxylic and aromatic anhydrides of structure:  EMI34.1  where X is chosen from:  EMI34.2   8. Composition according to Claim 7, characterized in that the organic compound is an ester of an acid chosen from the class formed by isophthalic acid, terephthalic acid, trimellitic acid, phthalic acid, l pyromellitic acid, acid  <Desc / Clms Page number 35>  3, 3 ', 4, 4'-biphenyltetracarboxylic and the aromatic acids of structure:  EMI35.1  where X is chosen from:    EMI35.2   9. Composition according to any one of Claims 1 to 6, characterized in that the aromatic anhydride is of structure:  EMI35.3  where X is chosen from the class formed by:  <Desc / Clms Page number 36>    EMI36.1    EMI36.2  fof'ioi j [or &commat; i \ oJL o \ o o  EMI36.3  where Y is H or F and Z is chosen from:  EMI36.4    EMI36.5  10. Composition according to claim 9, characterized in that the organic compound is an ester of an acid chosen from the class formed by isophthalic acid, terephthalic acid, trimellitic acid, phthalic acid, l pyromellitic acid and structural acids:  EMI36.6    EMI36.7  a where X is chosen from the class formed by:  <Desc / Clms Page number 37>    EMI37.1    EMI37.2  Z s o -8J jerL '0 \ 0 "TO  EMI37.3  where Y is H or F and Z is chosen from:    EMI37.4   11. Composition according to any one of Claims 1 to 6, characterized in that the aromatic anhydride is trimellitic anhydride.  12. Composition according to any one of Claims 1 to 6, characterized in that the anhydrous  EMI37.5  aromatic is pyromelite dianhydride. 13.-Composition according to any one of claims II and 12, characterized in that the organic compound is a white oil.  14.-Composition according to any one of claims 11 and 12, characterized in that the organic compound is 2-ethylhexanol.  15.-Composition according to any one of claims 11 and 12, characterized in that the organic compound is 2-ethylhexyl trimellitate.  16.-Composition according to any one of claims 11 and 12, characterized in that the organic compound is isononyl alcohol.  17. Composition according to any one of Claims 11 and 12, characterized in that the organic compound is triisononyl trimellitate.  <Desc / Clms Page number 38>    18.-A process for suppressing the dust given off by an aromatic anhydride which is solid at normal ambient temperatures, which process is characterized in that it comprises the treatment of the aromatic anhydride using at least one organic compound, according to which the organic compound is both liquid and substantially non-volatile at normal ambient temperatures and pressures and according to which the organic compound does not contain an anhydride functionality and in which the organic compound is applied to the surface of the aromatic anhydrous.    19.-A method according to claim 18, characterized in that the treatment comprises bringing the aromatic anhydride into contact with the organic compound, the organic compound being incorporated directly into the aromatic anhydride by stirring.    20.-A method according to claim 18, characterized in that the treatment comprises spraying the organic compound on the aromatic anhydride.    21.-A method according to any one of claims 18 to 20, characterized in that the treatment comprises applying the organic compound to the aromatic anhydride in the form of a solution of the organic compound in a volatile solvent.    22.-A method according to any one of claims 18 to 21, characterized in that the aromatic anhydride is treated using the organic compound to provide the aromatic anhydride with an amount of organic compound located in the interval d about 10 ppm (by weight) to about 100,000 ppm (by weight), based on the weight of the aromatic anhydride treated.  23.-A method according to any one of claims 18 to 21, characterized in that the aromatic anhydride is treated using the organic compound to provide the aromatic anhydride with an amount of organic compound located in the interval d '' about 100 ppm (in  <Desc / Clms Page number 39>  weight) to about 2,000 ppm (by weight), based on the weight of the treated aromatic anhydride.    24.-A method according to any one of claims 18 to 23, characterized in that the organic compound comprises a hydrocarbon.    25.-A method according to any one of claims 18 to 23, characterized in that the organic compound is chosen from the class formed by an ester, a mineral oil, a white oil, a polybutene, a hydrogenated polybutene, an alcohol, a polyalphaolefin, a vegetable oil and an animal oil.    26.-A method according to claim 25, characterized in that the organic compound is an ester of an acid chosen from the class formed by terephthalic acid, isophthalic acid, phthalic acid,  EMI39.1  trimellitic acid, adipic acid and oleic acid. 27.-A method according to any one of claims 18 to 26, characterized in that the aromatic anhydride est'choisi in the class formed by trimellitic anhydride, phthalic anhydride, pyromellitic dianhydride, dianhydride 3, 3 ', 4, 4'-biphenyltetra-  EMI39.2  carboxylic and aromatic anhydrides of, structure:  EMI39.3    EMI39.4  0 0 CH, CF, where X is chosen from:  Il il * i, Il 1 CF, Il 1 1 0 CH, CF,  <Desc / Clms Page number 40>   28.-A method according to claim 27, characterized in that the organic compound is an ester of an acid chosen from the class formed by isophthalic acid, terephthalic acid, trimellitic acid, phthalic acid, l 'pyromellitic acid, 3, 3', 4, 4'biphenyltetracarboxylic acid and aromatic acids of structure:  EMI40.1    EMI40.2  where X is chosen from: Q fn CF Il 1 Il 1 - O -, - C -, - C -, - S-et-cI 1 Il 1 CH2 0 CFj.,.  EMI40.3   29.-Process according to any one of Claims 18 to 26, characterized in that the aromatic anhydride is of structure:  EMI40.4    <Desc / Clms Page number 41>    EMI41.1  where X is chosen from the class formed by:  EMI41.2    EMI41.3  , ortOL \ oJL o o'O /  EMI41.4  where Y is H¯ or F and Z is chosen from:  EMI41.5    EMI41.6  30.-A method according to claim 29, characterized in that the organic compound is an ester of an acid chosen from the class formed by isophthalic acid, terephthalic acid, trimellitic acid, phthalic acid, l pyromellitic acid and structural acids:  EMI41.7  where X is chosen from the class formed by:  <Desc / Clms Page number 42>    EMI42.1    EMI42.2  rryZ'0 / and rQt0  EMI42.3  where Y is H or F and Z is chosen from:    EMI42.4   31.-A method according to any one of claims 18 to 26, characterized in that the aromatic anhydride is trimellitic anhydride.    32.-A method according to any one of claims 18 to 26, characterized in that the aromatic anhydrous is pyromellitic dianhydride.    33.-A method according to any one of claims 31 and 32, characterized in that the organic compound is a white oil.    34.-A method according to any one of claims 31 and 32, characterized in that the organic compound is 2-ethylhexanol.    35.-A method according to any one of claims 31 and 32, characterized in that the compound  EMI42.5  organic is tri-2-ethylhexyl trimellitate. 36.-A method according to any one of claims 31 and 32, characterized in that the organic compound is isononyl alcohol.  <Desc / Clms Page number 43>      37.-A method according to any one of claims 31 and 32, characterized in that the organic compound is triisononyl trimellitate.