US2310257A - Impregnating agent for vegetable fibrous materials - Google Patents

Description

Patented Feb. 9, 1943 nvrrasemme AGENT FOR VEGETABLE .rmaoUs MATERIALS Ludwig Bitter, The Hague, Netherlands, assignor, I

by direct and mesne assignments, to Albi Chemical Corporation, New York. N. Y., a corporation of New York No Drawing.

Application December 2, 1940, Se-

rial No. 368,253. In the Netherlands September 11 Claims.

out from the material treated it the same is in contact with a large excess of water for a sumcient period. This difllculty cannot be solved by using an insoluble fluoride such as calcium fluoride because the proportion of fluorine ions produced by this compound is so small that they have practically no preserving action.

It has been tried to obviate this difficulty by storing a sumcient amount of the preserving agent in a cavity of the object to be preserved. Obviously, however, this is only possible if the said object is of a suitable size, 1. e. in the case of wood having a suflicient thickness.

Another method of preventing the active agent from being washed away when in contact with water consists in fixing the. said agent in the fibres by a suitable addition. .This object can be attained by adding chromates or bichromates to the impregnating solution.

If the fibrous material is treated e. g. with a fluoride solution.

containing a substance of this character it appears that part oithe fluoride is present in the impregnated and dried material in such a form that it cannot be washed out to an appreciable extent with water, but that nevertheless the water coming in contact with the material is provided with a certain proportion of fluorine ions which produce a preserving action. Fully satisfactory results. however, are not always obtained by this method, since 'in some cases the fluorine ion concentration is-reduced below the limit required for a bactericide action, especially when the impregnated material treated is in contact with hard water, since in this case calcium .fluoride is produced, which is highly insoluble.

The packing materials such as cases, bags, baskets, etc., which are impregnated in this way also show the drawback that the foodstuffs contained in the same take up small amounts of fluoride so that it is generally not allowable to use the same tor thispurpose It has also been tried to preserve wood and other fibrous materials by impregnating the same with solutions of metal compounds in organic solvents from which the said metal compounds are deposited in insoluble or only very slightly soluble form in the fibres. For this purpose solutions of copper, zinc and aluminium salts of fatty-acids, naphthenic acids and the like in solvents such as naphtha can be used; emulsions oi the said substances are also suitable. For practical purposes, however, this method is generally too expensive; moreover the materials treated generally have an objectionable odour and the suppleness oi the fibres is decreased.

Other prior processes are based on the preserving action of the copper ion. It has e. 8. been proposed to impregnate jute bags by immerging the same in an ammoniacal copper oxide solution (the 'so-called Schweizer solution). This solution, however, presents the drawback that it has a dissolving action on the cellulose so that the material should only be immerged in the liquid for a very short time; e. g. 30 seconds, and

in this case it is not always possible to obtain a uniform impregnation. Moreover the-ammonia vapours produced bythe liquid render it necessary for the workmen to use gas masks and to take special precautions for protecting the skin against the liquid, while this method too is generally too expensive for practical purposes.

It has been suggested to combine the preserving action oi! the fluorine ions and the copper ions by impregnating the material to be treated with a solution of copper fluoride in ammonia. According to this process which has been described in German specification No. 226,975 the copper fluoride is precipitated from a copper salt solution with ammonium fluoride, separated from the liquid by filtration and subsequently dissolved in ammonia. When the fibrous material is impregnated with this solution the ammonia will readily evaporate, and the copper fluoride. is deposited in the fibrous'material in non-dissolved condition. v

This method too did .not'work satisfactorily. If relatively'ooncentrated solutions are used, the fibres are attacked by the ammoniacal copper solution and the material is accordingly tendered in the same way as described above in connection with the ammoniacal copper oxide solutions. If on the contrary very dilute solutions are employed the fibres are not appreciably attacked, but it has appeared that in this case the copper fluoride is already precipitated from the said dilute solution prior to the impregnating step so that it is deposited onthe fibres and not in the fibres in a form which is unsuitable for obtaining a satisfactory, uniiorm preserving action.

The invention provides an excellent impregnating agent for preserving vegetable fibrous materials which consists oi a solution copper fluoride, copper arsenite, or copper arsenate in ammonia, containing an organic base, aqueous or low volatility, i. e. an organic base which is practically non-volatile or only very slightly volatile. I have found that when using a solution 0! this character for preserving fibrous materials the insoluble copper compound is deposited in the fibres in a form which is very favorable in the present purpose. This is probably due to the fact that the copper compound remains in solution for a substantially longer period evenin very dilute solutions, so that it is slowly deposited in and on the fibres when the ammonia is evaporated from the impregnated material. Whether the said copper solutions are molecula or colloidal solutions is immaterial for the present purpose.

Owing to the very slow decomposition of the ammoniacal copper compound it is possible to use much more dilute solutions. This has the advantage that the fibres are practically not attacked by the solution, so that the material can be immerged in the said solution for a considerable period, c. g. 20-30 min. Moreover the dilute solutions are much more easy to handle since it is unnecessary to take special precautions against the ammonia vapours.

Organic bases which are especially suitable for the present purpose are the hydroxy amines, e. g. triethanol-amine. By the addition of compounds of this character to a dilute solution oi e. g. copper fiuoride in ammonia the properties of the said solution as an impregnating agent for wood and fabrics are substantially improved.

Substances such as triethanol-amine also have the property of increasing the wetting power of the solution so that it will more readily penetrate into the fibrous materials.

Theorganicbasescan beused as such orin the iorm oi water soluble compounds, and when the expression organic base is used in the specification and the appending' claims it is'meant to in-,

clude both the tree bases and their water soluble compounds.

I have found it to be adavntageous to prepare the impregnating liquid not by dissolving previously precipitated copper fluoride inthe liquid containing ammonia, but by adding a soluble fiuoride to a solution oi a soluble copper, salt containing ammonia and the organic base. Comparativctests have shown that solutions obtained in the last mentioned way have a better, more unii'orin preservative action on the fibrous material than solutions obtained from previously precipitated copper fiuoride. Similar results were obtained with the other copper compounds used according to the invention. It is not improbable j that this improvement is partly dueto the presence in the final product of the sodium sulphate or sodium chloride, produced by the interaction oi copper sulphate or copper chloride withsodium fiuoride, arsenite or arsenate.

The action oi the impregnating liquid according to the invention can further be improved by adding mordants having the property of fixing the compounds on the fibre. Derivatives oi phthalic acid and of naphthol and compounds with a double phenyl nucleus are suitable for A considerable improvement may be obtained by incorporating into the impregnating liquid substances which have a swelling action on the fibres without appreciably attacking the same as described in my co-pending U. S. A. application Serial No. 368,252, filed Dec. 6, 1940. As suitable additions for this purpose I may mention borax and other soluble borates, cyanides, humates, saponins, some glucosides, saccharates, gluconates and other salts of carboxylic acids, salts of sulphonic acids and alkyl sulphuric acids, amines and amides, and salts the anions or kations of which are indicated in the well known Hofmeister range, as exerting a swelling action, such as rhodanides, nitrates, iodides, bromides,

- chlorides and chlorates. A swelling action is generally also exerted by the organic bases or their water soluble compounds used according to the invention. This swelling action has a favourable efiect on the impregnating proces since the impregnating liquid penera'tes more easily into the fibres so that the copper fluoride is deposited more uniformly throughout the material.

The impregnating agent according tothe invention preferably does not contain more than 7- grams of copper per litre. An impregnating agent orthis composition has an excellent preservative action on the fibrous material treated therewith without appreciably attacking the The invention will be illustrated by the following examples:

Example 1 Kilograms Crystalline copper sulphate 4.5 Sodium fluoride-and 1.6 Ammonia 28% 5.0

are introduced into a'container containing stirring and cooling devices. An exothermic reaction occurs and it is necessary to cool the reaction mixture sinc'esubstantlal amounts of ammonia will be lost by evaporation ii the temperature of water in a proportion of 30-50 parts of water on 1 part of the basic liquid.

Example 2 v i i Kilograms Crystalline copper ch1oride 3.9 Sodium arsenite and-- 2.1 Ammonia 28% 6.0 v

are made to react as described in'Example 1.

when the reaction i finished 90 grams of ethylenediamine and 150 cm. of a 10% solution oi equal parts of ammonium rhodanide and amthis purpose. but other well known mordants may 7 ,alsobeused.

monium humate in dilute ammonia containing 25% 01' NH: are added.

' The solution'obtained in this way is the basic liquid, which is diluted with 40-60 parts of water in order to produce the impregnating liquid properly speaking.

Solutions having a similar preservative action are produced when substituting in the examples arsenates for arsenites or when using two or more of the said substances at the same time.

The invention is especially valuable for preserving bags, e. g. jute bags, transport cases and perature of 38 C. for a period of 28 days.

jute bag was subjected to a baskets. Packing materials of this character have often to be stored or kept in a humid atmosphere under conditions which are very favourable"'for the development of micro organisms. Especially serious diificulties are encountered when using sand bags which are often destroyedin a relatively short time.

The excellent results obtained byfthe treatment claimed are shown by the following test:

A jute bag is impregnated with theliquid described in Example'l, dried and, subsequently washed for a period of '7 days in running water. The bag is now introduced into a container Where it. is subjected to a rotting process at a tern;

non-impregnated similar rotting treatment.

It appeared that at the end of'the period of 28 days the tensile strength of the-impregnatedbag was reduced to about 75% of. the original strength,--whereas the same-value for the nonimpregnated bag after a rotting period of only 7 days was not'more than although in this case the preliminary treatment with water during 7 days was omitted. This experiment shows that the mechanical properties of the impregnated bag were only slightly affected although the conditions in this test were much harder than they will ever be in practice.

The invention is not only serving fabrics, wood and against deterioration by and insects, but also and protecting plants against insect pests. For the last mentioned purposes the preserving agent according to the invention can be sprayed on the important for premicro organisms, fungi other fibrous materials for combating plant diseases plants according to the usual methods. The

solutions used in this case are preferably diluted to a lower concentration than those employed for impregnatingfabrics and wood. By way of Example I may mention that suitable solutions may be obtained by diluting the basic solutions described in the examples with water in a pro-. portion of 100-300 parts of water on 1 part of the solution. It is advantageous to increase the proportion of ammonia and organic base in the said dilute solutions in order to keep the copper compounds better dissolved, whereas the mordants and the substances having a swelling action may be omitted in this case.

I claim: q l 1. A composition for preserving fibrous mate-' rials by combating harmful micro-organisms,

a substance having a swelling action comprising an aqueous solution containing ammonia, a hydroxy amine of low volatility and'having a marked stabilizing effect on copper ammonia compounds in dilute aqueous solutions and improving the impregnating and wetting proper- I ties of such solutions, and at least 'one' substance of the group consisting of copper fiuoride,,cop

per arsenite, and copper arsenate.

2. A composition for preserving fibrous-materials by combating harmful: micro-organisms, comprising an aqueous solution containing am,-

monia, triethanolamine, and at least one substance of the group consisting of copper fluoride,

copper arsenite, and copper arsenate'.

3. A composition for preserving fibrous materials by combating harmful micro-organisms,

- comprising an aqueous solution containing ammonia, ethylene diamine, and at least one 'sub-. stance of the group consisting of copper fluoride, copper arsenite, and copper arsenate.

4:. A composition for preserving fibrous matesenate; further ammonia,

rialsby comprising an aqueous solution containing at further ammonia, and "a a marked stabilizing effect comprising an aqueous solution containing at least one substance of the group consisting of copper fluoride, copper arsenite, and copper ara hydroxy amine of low volatility and having a marked stabilizing effect on copper ammonia compounds in dilute aqueous solutions and improving the impregnating and wetting properties of said solutions, and a mordant consisting'of a mixture containing phthalic acid'and naphth'ol compounds.

5. A composition for preserving fibrous materials by combating harmful micro-organisms,

comprising an aqueous solution containing at least one substanceof the group consisting of, copper fluoride, copper arsenite, and copper arsenate; further ammonia, triethanolamine, and

a mordant consisting of betanaphthol, phenolphthalein, and diphenylamine.

6. A composition for preserving fibrous matecombating harmful micro-organisms,

least one substance of the group consisting of copperfiuoride, copper arsenite, and copper ar senate; a hydroxy amine of low volatility and having a marked stabilizing effect on copper ammonia compounds in dilute aqueous solutions and improving the impregnating and wetting properties of such solutions, and a swelling substance harmless to the fibres and improvin the penetration of said solution of copper ammonia compounds into said fibres.

'l. A'composition for preserving fibrous materials by combating harmful micp-organisms, comprising an aqueous solution containing at least one substance of the group consisting of copper fiuoride,,copper arsenite, and copper arsenate; further ammonia, a. hydroxy amine of low volatility and having a marked stabilizing effect on copper ammonia compounds in dilute aqueous solutions and improving the impregnating and wetting properties'ofsuch solutions, and

materials and being harmless thereto,' said swelling substance being one selected from a group consisting of soluble borates, cyanides, humates, saponins,glucosides, saccharates, gluconates, carboxylic acids, salts of sulphuric acids, amines and amides, and rhodanides, nitrates, iodides, bromides,-chlo rides, and chlorates. 8. Acomposition for preserving fibrous materials by combating harmful micro-organisms, comprising an .aqueoussolution containing at least one substance of the group consisting of copper fluoride, copper arsenite, and copper arsenate; v hydroxy amine of low volatility and having on copper ammonia compounds in dilute aqueous solutions and improving the impregnatingand wetting properties of such solutions, the said solutioncontaining less. than 7 grams of: copper per litre.

9. The process of producing a compound for preserving fibrous materials by combating harm-,- ful micro-organisms, which consists in adding a substance of the group of soluble fluorides, arsenites, and

. ties of such solutions.

rials by combating harmful micro-organisms,

10. The process for preserving fibrous materials, comprising impregnating the said material sulphonic acids and alkyl' by treating it with an aqueous solution containsists in spraying against said plant an aqueous ing at least one substance oi the group consistsolution containing ammonia, triethanolamine, in: 01' copper fluoride, copper arsenite, and copper and at least one substance ofthe group consistarsenate; further ammonia and triethanolamine; ing or copper fluoride, copper arsenite, and copand dryinz'the material thus treated. 5 per arsenate.

11. The method for combating plant diseases, LUDWIG RI'I'IER. insect pests, and micro-organisms; which con-