WO1987006177A1

WO1987006177A1 - Aqueous solutions of rosin and use of the solutions

Info

Publication number: WO1987006177A1
Application number: PCT/SE1987/000152
Authority: WO
Inventors: Carl-Erik Sundman; Loulou Marie WIKSTRÖM
Original assignee: Kemira Kemwood Ab
Priority date: 1986-04-07
Filing date: 1987-03-24
Publication date: 1987-10-22
Also published as: AU7209887A; SE8601548D0

Abstract

Ammoniacal aqueous solutions containing rosin, metal and a surface active agent which is a nonionic tenside or a quaternary ammonium compound. The surface active agents solubilize the combination of metal and rosin and the solutions are particularly suitable for use as treatment agents for wood and wood based products to give water repellent effect and also a fungicidal effect as the solutions contain a preservative metal.

Description

Aqueous solutions of rosin and use of the solutions The present invention relates to arnmoniacal aqueous solutions of rosin and metal which solutions contain a surface active agent. The solutions according to the inven- 5. tion give water repellent effect and are suitable for treatment of wood. In the treatment of wood they also give a fungicidal effect.

Rosin is one of the most common hydrophobing agents at the ^* production of paper and herein they are most often

-JO. used as internal sizes, ie they are added to an aqueous suspension of fibres. For water repellent treatment of wood and wood products agents based on alkyd resins, drying oils, waxes etc are mainly used. However, it is per se known to treat wood with rosin to obtain a water repellent

₁₅. effect. US patent 2768910 discloses impregnation of wood with an ammoniacal solution of the reaction product of colophony and an acid, such as maleic acid, for water repellency, hydrophobing. In order to obtain resistance to biological attacks it is known to utilize aqueous ammo-

20. niacal compositions based on metals, particularly copper, in combination with acids or quaternary ammonium compounds for impregnation of wood. However, such compositions, which are disclosed for example in US patents 4001400 and 4193993 and European patent 58142, do not have any water repellent

25. effect.

A very good water repellent treatment of wood, wood products and wood based products can be obtained by utiliz¬ ation of a combination of metal and rosin material. It is supposed that the metal hereby precipitates and fixes the 30. rosin material in the wood. Besides the improved water repellent effect a certain fungicidal effect is also ob¬ tained when metals such as copper, zinc etc are used. However, mixtures of solely metal and rosin in an ammo¬ niacal solution cannot be used without technical problems. 35.To avoid precipitations, phase separation etc in such solutions it is necessary to use amounts which are outside those appropriate in practical use and it is also necessary to utilize high temperatures. There is a need for satisfactory water repellency treatment of wood with compositions giving good economy, which do not have any environmental drawbacks and which can be applied by technically simple processes. The present 5. invention offers such compositions and treatment. The compositions of the invention are aqueous and solvents such as white spirit and similar nonpolar solvents do not have to be used. The compositions can be used in one step pro¬ cesses, they can have suitable concentrations for practical

10. use and they can be used at normal treatment temperatures.

The compositions give the treated materials resistance to water absorption and thus improved dimensional stability and they also give the treated materials decay protection.

According to the present invention it has been found

15. that by the use of certain surface active agents ammoniacal aqueous solutions of metal and hydrophobing rosin can be obtained wherein the active components are entirely dis¬ solved and which solutions have good storage stability, ie phase separation and precipitations do not occur, and this

20. at concentrations which are suitable for practical use. The solutions according to the invention are particularly suitable as treatment agents for wood in order to make this water repellent and, when the solutions contain a preser¬ vative metal, they also give a decay protection.

25. The present invention thus relates to an ammoniacal aqueous solution containing rosin, a preservative metal and a surface active agent which is a nonionic tenside having an HLB-value of at least 10 or a quaternary ammonium com¬ pound containing at least one organic hydrophobic group

30. with 6 carbon atoms or more.

The rosin is the essential hydrophobing substance in the compositions. By rosin is herein understood the for hydrophobing, particularly in papermaking, per se well known types which essentially consist of polycyclic organic

35. acids, resin acids, of abietic or pimaric type. Thus the compositions according to the invention can contain wood, gum and especially tall oil rosin which can be crude, refined, proportioned, hydrated, saponified and/or forti- fied in a known manner. Preferably rosin which has been reacted with an acid, eg acrylic acid, and most preferably fortified rosin, ie rosin which has been reacted with an alpha-beta-unsaturated polybasic acid is used, eg fumaric 5. acid, maleic acid, itaconic acid or anhydrides of these.

The present solutions contain a so-called preser¬ vative metal, ie a metal which gives a fungicidal effect against wood destroying fungi. The metal in the composi¬ tions is suitably copper, zinc, tin, magnesium, calcium or

10. nickel. Copper or zinc is most suitably used as the preser¬ vative metal and preferably copper. The metal in the com¬ positions thus have two functions, it influences the rosin material and improves and prolongs the water repellent effect of this and it also gives decay protection when the

15. compositions are used as wood preservatives. The term metal here of course refers to metal cations and not to the substances in metallic form. It is per se possible to start from metallic metal when preparing the solutions and to dissolve a sufficient amount of this by oxidation. However,

20. it is more suitable to use, as metal source, a metal com¬ pound which is soluble in an aqueous ammoniacal solution and to use for example oxides, hydroxides, carbonates, arsenates, sulphates, chlorides, acetates etc.

The aqueous solutions according to the invention

25. shall be ammoniacal and thus they contain an ammoniacal component by which is meant ammonia, ammonium salts and short chain amines or salts of these. Short chain volatile amines,, alkyl or preferably hydroxyalkyl amines having 1 to 4 carbon atoms, work in the same manner as ammonia and

30. ammonium salts and solubilize the metal in the compositions and also to a certain extent the rosin material. Examples of short chain amines are ethanolamine and isopropanol- amine. It is, however, preferred that the ammoniacal com¬ ponent is ammonia or ammonium salt, or a mixture of ammonia

35. and ammonium salt. As examples of suitable ammonium salts can be mentioned ammonium carbonate, ammonium bicarbonate and ammonium acetate.

According to the present invention it has been found that certain surface active agents, tensides, can solubi¬ lize combinations of metal and rosin and thus make the preparation of aqueous solutions of such combinations possible. According to the invention a nonionic tenside or 5. a surface active quaternary ammonium compound is used for this purpose. The nonionic tensides which are used have an HLB-value of at least 10, ie they have hydrophilic tenden¬ cies. As examples of suitable types of nonionic tensides can be mentioned ethoxylated alkyl phenols, ethoxylated

10. fatty alcohols, ethoxylated fatty acids, ethoxylated deri¬ vatives of fatty acid esters, or partial esters, of poly¬ valent alcohols with 2 to 8 carbon atoms, or anhydroderi- vatives of these, such as glycol, glycerol, sorbitol, sorbitan etc. In these alkyl and fatty parts, respectively,

15. are present and hereby is understood alkyl groups contain¬ ing at least 8 carbon atoms and fatty residues containing at least 8 carbon atoms. Ethoxylated alkyl phenols are particularly preferred. When the solubilizing agent in the present compositions is a nonionic tenside this is suitably

20. used in combination with an auxiliary chemical which is a short chain alcohol, suitably with 1 to 5 carbon atoms, eg methanol, ethanol, propanol or butanol.

The other type of surface active agent which accord¬ ing to the invention is used as solubilizing agent for the

25. combination of metal and rosin is a quaternary ammonium compound which contains an organic hydrophobic group with at least 6 carbon atoms. Particularly suitable are quater¬ nary ammonium compounds which can be characterized by the general formula

30. Rl

R - N ⁺ - R_χ X^"

Rl 35. wherein R is the above defined hydrophobic group and the substituents Rτ_ independent of each other are lower alkyl or hydroxyalkyl groups having 1 to 4 carbon atoms, aryl or aryl substituted alkyl groups wherein the alkyl groups has 1 to 3 carbon atoms, particularly benzyl groups, or has the same meaning as R. X is an organic or inorganic anion. The hydrophobic group or groups R can be straight or branched, saturated or unsaturated, aliphatic groups having at least 5. 6 carbon atoms, suitably with from 6 to 18 carbon atoms, or alkylaralkyl groups where the alkyl substituent suitably contains 6 to 18 carbon atoms. It is preferred that the compounds contain one or two hydrophobic groups as defined above. As examples of suitable quaternary ammonium com-

1o. pounds can be mentioned tetradecyltrimethylammonium brom¬ ide, cetyltrimethylammonium chloride, dihexadecyldimethyl- ammonium chloride, (alkylbenzyl)trimethylammonium chloride and alkylbenzyldimethylammonium chloride wherein the carbon chain length distribution of the alkyl groups in the two

15. last mentioned compounds is within the range given above. As quaternary ammonium compound it is particularly pre¬ ferred to use such compounds which contain two organic hydrophobic groups and two lower alkyl groups and those which contain one organic hydrophobic alkyl group and three

20. lower alkyl groups or a benzyl group and two lower alkyl groups, such as alkylbenzyldimethylammonium chloride wherein R is a mixture of alkyl groups from C_β to Cn.8' which is called benzalkonium chloride. The best solutions are obtained with these types of quaternary ammonium com-

25. pounds. Mixtures of quaternary ammonium compounds of the benzalkonium chloride type and other quaternary ammonium compounds usually give better results than when only the latter are used. The anion X can for example be acetate, propionate, lactate, 2-ethylhexanoate, ethylsulphate or

30. chloride ion.

Combinations of quaternary ammonium compounds and nonionic tensides, eg such as those defined above, can of course also be used.

The primary function of the quaternary surface active

35. ammonium compound in the present formulations is in order to obtain aqueous solutions of combinations of metal and rosin. However, quaternary ammonium compounds are per se known as fungicidal agents for use for example as wood preservatives and when the present solutions contain, besides the hydrophobing rosin material, both preservative metals and quaternary ammonium compounds a treatment solu¬ tion is obtained which is especially advantageous as it 5. confers to wood both good water repellency and protection against wood destroying fungi.

In the present solutions the rosin material shall be present in an amount sufficient for obtaining the desired water repellent effect and the amount also varies with the

10. application method. The amount of metal with regard to rosin shall be sufficient for obtaining the desired fixa¬ tion of rosin in the wood. The weight ratio of metal to rosin in the solutions should be at least 1:40 and prefer¬ ably at least 1:20. The upper limit is not critical and

15. high amounts of metal with regard to rosin can be used, up to 5:1 and thereabove, to obtain formulations which give as well good water repellency as good fungicidal effect. The weight ratio of metal to rosin is suitably in the range of from 1:40 to 5:1 and preferably within the range of from

20. 1:20 to 2:1.

The surface active agent in the compositions is used in amounts for solubilizing the combination of metal and rosin. The weight ratio of surface active agent to rosin should for this purpose be at least 1:10 and preferably at

25. least 1:1. In the same way as for the metal content the upper limit for the tensides which are used is not critical but mainly set by economical reasons. For quaternary ammo¬ nium compounds it can, with regard to the fungicidal effect, be advantageous to use fairly high amounts. It is

30. suitable to have a weight ratio of surface active agent to rosin in the ^'solutions within the range from 1:1 to 10:1 and the ratio is preferably within the range from 2:1 to 5:1. When the nonionic tensides are used it is suitable, as stated earlier, to use a lower alcohol as auxiliary chemi-

35. cal and this can then be used for example in weight ratios to the nonionic tenside of from 1:10 to 10:1.

The ammoniacal component, ammonia, ammonium salt, short chain amine or salt of this, is used for solubiliz- ation of the metal and should be present in an amount of at least one mole per mole of metal. However, the ratio bet¬ ween ammoniacal component and metal can vary within very wide limits. Usually a mole ratio of ammoniacal component 5. to metal within the range of from 1:1 to 20:1 is used, preferably within the range 4:1 to 10:1. The ammoniacal component, and optional other base, eg sodium hydroxide, shall give the final solution a pH of at least 8.0 and preferably of at least 9.0.

10. Particularly preferred solutions according to the invention contain copper, rosin and as solubilizing agent a quaternary ammonium compound which contains one or two hydrophobic groups, and which preferably is benzalkonium chloride, optionally in combination with another quaternary

15. ammonium compound or a nonionic tenside.

The solutions according to the invention are suitably prepared by forming and mixing two solutions, one solution of the rosin material which is made alkaline and one solu¬ tion of metal and surface active agent which is made ammo-

20. niacal. At the preparation of the solution of the rosin material it is suitable to use elevated temperature, about 50 to 60°C, while the solution of metal can be prepared at room temperature or elevated temperature. According to the invention concentrated ammoniacal solutions of metal and

25. rosin can be prepared without problems with phase separat¬ ion etc and the solutions can be diluted to the desired use concentration before its utilization.

The combination of metal, rosin and surface active agent means that total water solubility can be obtained and

30. this is important with regard to storing and stability and at impregnation of wood so that separation into different phases, with resulting diminished effect, does not occur. The aqueous solutions according to the invention are part¬ icularly suitable as impregnating agents for timber, wood

35. and wood based products for water repellent treatment conferring improved dimensional stability and they are hereby used in one-step processes. The use of the composi¬ tions as wood treatment agents is part of the present invention. It is assumed that when the pH, as natural, decreases in the wood a metal-rosin complex is precipitated after treatment with the present solutions. As the present formulations are aqueous solutions a good penetration of 5. the cell walls is obtained and thus a good and prolonged water repellent effect is obtained. By fixation of the rosin a substantially improved water repellent effect is obtained in comparison with the use of rosin without metal. As has been mentioned above, the present compositions also

10. give decay protection and this can, by increasing the amounts of metal and quaternary ammonium compounds, be made to correspond to a fully satisfactory protection against biological attacks.

The present solutions can for example be utilized for

15. treatment of poles, sawn timber, finished wood products such as joineries and wood based products such as particle board, plywood and board. The compositions of the invention are particularly valuable for treatment of products intended for outdoor use or in environments where they will

20. be subjected to repeated moistening and drying.

The solutions can be applied to the material by any known technique, for example by dipping, spraying, brushing and vacuum/pressure impregnation. It is particularly pre¬ ferred to use treatment methods which utilize pressure

25. differences for penetration of the liquid.

At - the treatment of wood, wood products and wood based products the amount of rosin in the solution should suitably be within the range of from 0.1 to 15 per cent by weight, and at pressure and/or vacuum impregnation prefer-

30. ably within the range of from 0.5 to 5 per cent by weight. The invention is further illustrated in the following examples which, however, are not intended to limit the same. Parts and per cent relate to parts by weight and per cent by weight respectively, unless otherwise stated.

35. Example 1

Three solutions of rosin with dry contents of 1, 2 and 10% respectively, solutions la, lb and lc respectively, were prepared according to the following: Solution la 60 g NH₃ (25%) 1.66 g NaOH 8.4 g ethanol 5. 920 g water were mixed and warmed to about 50°C. 10 g of rosin fortified with fumaric acid were added under conti¬ nued heating and stirring. Solution lb 60 g NH₃ (25%)

10. 1.6 g NaOH

8.4 g ethanol

420 g water were mixed and warmed to about 50°C. 10 9 °f rosin fortified with fumaric acid were added under conti¬ nued heating and stirring.

15. Solution lc 60 g NH₃ 10 g ethanol 1 g NaOH

19 g H₂0 were mixed and warmed to about 50°C. 10 g of rosin 20. fortified with fumaric acid were added under continued heating and stirring.

Starting from the above solutions of rosin aqueous solutions of metal and rosin according to the invention were prepared. At the preparation warm rosin solution was 25. added to water and the metal was then admixed. Solution I

20 g ammoniacal copper (Cu=11.3%, 6.4 moles NH₃/mole Cu) 20 g benzalkonium chloride (50%)

250 g of rosin solution la 30. 710 g water

The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was

10.5.

Solution II 35. 20 g ammoniacal copper solution (Cu=11.3%, 6.4 moles NH₃ per mole Cu)

33 g benzalkonium chloride

500 g of rosin solution la 447 g water

The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was 10.5. 5. Solution III

20 g ammoniacal copper solution (11.3% Cu, 6.4 moles NH₃ per mole Cu) 55 g benzalkonium chloride 500 g of rosin solution lb 10. 425 g water

The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was 10.5.

Solution IV 15. 20 g ammoniacal copper solution (Cu=4%, 6.4 moles NH₃ per mole Cu)

4 g tetradecyltrimethylammonium bromide (100%) 10 g of rosin solution lc

66 g water 20. The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was

10.5.

Solution V

10 g ammoniacal copper solution (Cu=4%, 6.4 moles NH per 25. mole Cu

7.2 g of a mixture (1:1) of an ethoxylated alkylphenol having an HLB-value of 14.1 and ethanol

10 g of rosin solution lc

72.8 g water 30. The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was

10.5

Solution VI

10 g ammoniacal copper solution (Cu=4%, 6.4 moles NH₃ per 35 _m mole Cu)

5 g of a mixture (1:1) of an ethoxylated nonylphenol having an HLB-value of 16.0 and ethanol 10 g of rosin solution lc 75 g water

The obtained solution was clear and dark blue and showed good storage stability. The pH of the solution was 10.5 ⁵* Example 2

The effect of the solutions with regard to retarding water absorption was investigated according to the follow¬ ing:

Veneer samples of pine with the dimensions 15x7x0.5 10. cm were used. For each test 5 pieces were used. The treat¬ ment was carried out with pressure/vacuum impregnation and the pieces were subjected to vacuum at 0.01 MPa for 15 minutes, and to a pressure of 1 MPa for 30 minutes. The impregnated test pieces were dried to constant weight in a 15. drying chamber at 55°C and then conditioned at 65% RH. The water repellent effect was then determined according to the following:

The effect of retarding water absorption is here called the WR-effect (water repellent) and given the 20. following definition:

WR-effect =^• (W_ut - t)/ _ut x 100 % where W_u^- is weight increase in per cent for untreated material and ^ is weight increase in per cent for treated material. 25. In the test the test pieces were placed in a rack after conditioning and this was lowered into water at room temperature. The water absorption was followed by weighing the pieces at certain intervals until 70 hours had passed. When the weight increase of the test pieces was more than 30. 35% and the wood material could be expected to be in a fully swelled condition the pieces were once again condi¬ tioned to equilibrium at 65% RH. This represents a cycle, conditioning-swelling-conditioning.

The results are shown below as WR-_j_ g^ = as calculated 35. at measuring after 1.5 hours exposure in water in the 70 hours cycle.

As a comparison the corresponding test was made with a 10% ammoniacal dispersion of a rosin-fumaric acid adduct without metal.

^1,5 h Solution I 41%

Solution II 44%

5. Solution III 50%

Comparison 31%

Example 3

Sapwood of pine (P. sylvestris) of the dimensions

500x50x20 mm were pressure impregnated according to the

10. Bethell method. The copper content of all impregnation solutions was 0.35% w/w, except for the CCA-solution which had a copper content of 0.20% w/w. After fixation, drying and conditioning 5 test pieces from each treatment were exposed outdoors in horizontal position. The water absorbed

15. by the test pieces was recorded by weighing as a function of time.

The following compositions were investigated: A. CCA-composition, Cu0=14.8%, Cr2θ =26.6%, AS2θ5=34.0%. A conventional impregnating agent. Comparison.

20. B. A Cu(NH₃) composition, Cu:NH₃ = 1:6.4 mole/mole. Comparison.

C. A composition of Cu, NH₃ and benzalkonium chloride, Cu:NH₃ = 1:5 mole/mole, Cu:benzalkonium chloride = 2:1 w/w. Comparison.

25. D. A composition of Cu, NH₃ and two quaternary ammonium compounds, benzalkonium chloride and a dialkyldimethylammonium chloride having a carbon chain length distribution of 50% C8 and 50% CIO. Cu:NH₃ = 1:5 mole/mole, Cu:benzalkonium chloride = 1:1 w/w,

30. Cu:dialkyldimethylammonium chloride = 1:1 w/w. Comparison.

E. An aqueous solution according to the invention containing rosin fortified with fumaric acid, Cu, NH₃ and two quaternary ammonium compounds, benzalkonium chloride and dialkyldimethylammonium chloride as in D. Rosin:Cu =

35. 1.4:1 w/w, Cu:benzalkonium chloride = 1:12 w/w, Cu:dialkyldimethylammonium chloride = 1:2.6 w/w.

F. An aqueous solution according to the invention containing rosin fortified with fumaric acid, Cu, NH and a nonionic tenside, ethoxylated nonylphenol with 12 ethoxy groups and an HLB-value of 14.1. Rosin:Cu = 2.8:1 w/w,

Cu:ethoxylated nonylphenol = 1:14 w/w.

In the table below the relative water absorption in

5. relation to untreated wood is given. The values are normalized and the standard deviation in each group has been calculated. The points of measuring have been selected in such a manner that the test pieces have been weighed after that they have been exposed to rain in order to

10. facilitate the evaluation of the effect of the different treatments.

Table

Normalized moisture ratio (+- standard deviation) Product after 10 17 27 45 53 days

Untreated 100(9) 100(11) 100(14) 100(9) 100(7)

15,

A 115(17) 120(15) 110(17) 105(14) 111(11

B 100(11) 118(12) 103(15) 100(11) 111(11)

C 92(14) 109(15) 94(13) 100(9) 108(15)

D ^* 80(4) 99(13) 86(14) 95(13) 99(13)

E 59(6) 65(5) 61(4) 70(3) 70(3)

20,

F 76(3) 92(8) 72(5) 82(6) 86(8)

Claims

1. Ammoniacal aqueous solution containing rosin, characterized in that it contains rosin in combination with a preservative metal and a surface active agent which is a nonionic tenside having an HLB-value of at least 10 or a quaternary ammonium compound containing at least one or¬ ganic hydrophobic group having 6 carbon atoms or more.

2. A solution according to claim 1, characterized in that the preservative metal is copper or zinc.

1 0 3. A solution according to claim 1 or 2, character¬ ized in that the surface active agent is a quaternary ammonium compound which contains one alkyl group with 6 to 18 carbon atoms and three lower alkyl groups or one benzyl group and two lower alkyl groups or a quaternary ammonium

₁₅_ compound which contains two alkyl groups with 6 to 18 carbon atoms and two lower alkyl groups.

4. A solution according to any of the preceding claims, characterized in that the weight ratio of metal to rosin is at least 1:40 and in that the weight ratio of

20 surface active agent to rosin is at least 1:10.

5. Use of an ammoniacal aqueous solution containing rosin, a preservative metal and a surface active agent which is a nonionic tenside having an HLB-value of at least 10 or a quaternary ammonium compound, containing at least

25 one organic hydrophobic group having 6 carbon atoms or more, fo treatment of wood and wood based products.

6. Use of a solution according to claim 5, whereby the preservative metal is copper or zinc.

7. Use of a solution according to claim 5 or 6,

30 whereby the surface active agent is a quaternary ammonium compound which contains one alkyl group having 6 to 18 carbon atoms and three lower alkyl groups or one benzyl group and two lower alkyl groups or a quaternary ammonium compound which contains two alkyl groups having 6 to 18

__ carbon atoms and two lower alkyl groups.

8. Use of a solution according to any of claims 5 to 7, characterized in that the weight ratio of metal to rosin in the solution is at least 1:40 and the weight ratio of surface active agent to rosin is at least 1:10.