NO160776B - EMERGENCY EXPLOSION OF WATER-I OIL TYPE. - Google Patents

Description

Tanning agent.

The present invention relates to a tanning agent, particularly for use in tanning leather.

It is already known that different hides and skins can

is tanned using polyacrylic acid, polymethacrylic acid or sara polymers of these acids. These materials can be used as the only tanning agents or they can be used as pre-tanning or re-tanning agents, either before or after the application of other tanning agents,

like for example. chromium, zirconium, natural tanning agents and synthetic tanning agents. The use of these agents, however, has a major disadvantage in that they often give cracks to the grain of the leather, and this even occurs in some cases with heavily greased leather. Most synthetic

tanning agents f®<p>år cases do not crack in this way even when they are used without greasing. Compositions made from the tanning agent and a fat agent, such as e.g. an oil, has the disadvantage that there is a strong separation of the oil from the composition during storage after a few days.

The purpose of. the present invention is to provide a new agent which has advantageous tanning properties. It has been discovered that such tanning compositions can be made using an acrylic polymer.

According to the present invention, a tanning agent is provided which is characterized in that it comprises a copolymer of a mixture of 80-90 weight percent acrylic acid and/or methacrylic acid and 20-10 weight percent of an unsaturated sulphation product of an animal or a vegetable oil.

In a preferred embodiment, the tanning agent comprises a copolymer of a mixture of 80-90 weight percent methacrylic acid and 20-10 weight percent of an unsaturated sulphation product of castor oil, clove oil, spermaceti oil, cod liver oil or soybean oil. In another embodiment, the tanning agent comprises a copolymer of a mixture of at least 75% by weight methacrylic acid and up to 25% by weight acrylic acid, calculated on the acid component, and 20-10% by weight of an unsaturated sulphation product of claw oil, spermaceti oil, cod liver oil or soybean oil.

The sulfated oil with which the unsaturated acid is polymerized is an oil in which the degree of sulfation has not been great enough to completely eliminate all unsaturated bonds in the product. Thus, the degree of sulphation can be such that it can remove all but one of the unsaturated bonds in the oil. In the oils that also contain hydroxyl groups, sulphation can be carried out solely on the hydroxyl groups, so that all the unsatd. bonds remain essentially pristine, or the sulphation can convert both the hydroxyl groups and parts of the unsaturated groups into sulphates. For example, in olive oil, which contains a glyceride of oleic acid as a main component, sulfation can introduce sulfate groups at one or two of the three unsaturated points in the glyceride molecule, leaving one or two of the unsaturated groups essentially intact or unmodified. If olive oil must be mentioned, it can be used instead of any of the other animal and vegetable oils that contain one or more glycerides of unsaturated fatty acids with long chains, such as e.g. from 12 to 20 carbon atoms. Examples of these oils include:

The production of the even partially unsaturated sulphation products of these oils is well known and many are commercially available.

The copolymerization is effected in an aqueous medium in which the sulfated oil is dissolved, for example at a concentration of 5 to 15 percent by weight. soluble chain transfer agent An aqueous solution of a chain transfer agent, if such an agent is used, can also be dissolved directly into the monomer and this solution can then be added to - the ..sulphated oil/catalyst solution in the bottle.' The sulfated oil/catalyst solution (which may also contain a chain transfer agent) can be held at room temperature or raised as high as 97°C or higher (so that reflux occurs) and held at the desired temperature while the acid monomer is added. The addition of the acid monomer results in the copolymerization of such an acid with the unsaturated sulfated oil so that a product according to the present invention is formed, which product is very effective as a tanning agent for leather, and has the advantage that it causes tanning without giving cracks to the grain of the leather even without fat treatment of the leather.

The relative amounts of acid monomer and sulfated oil are 80 and 90 weight percent monomer and 20 to 10 weight percent oil, based on the mixture. In other words, the amount of monomer used is approx. 4 to 8 times greater than the quantity of sulphated oil. The amount of initiator is from 0.5 to 6 percent by weight of the monomer. Examples of initiators include hydrogen peroxide, ammonium persulfate, sodium persulfate and potassium persulfate.

The amount of chain transfer agent depends on the individual agent and its effectiveness in controlling the molecular weight of the copolymer. Usually, the amount of chain transfer agent is correlated with the amount of initiator so that the result is a formation of a copolymer which, in acid form, at approx. 33$ concentration in water and at 25°C, will have a viscosity in the range from 15 to 300 poise. No chain transfer agent is necessary if the amount of initiator used is large enough to form a low molecular weight copolymer in the specified range. It is calculated that the most suitable molecular weight range for the product is from approx. 5,000 to 50,000 on average. Examples of chain transfer agents include hydroxylamine or salts thereof, such as e.g. hydroxylamine sulfate, mercaptoethanol, mercaptopropanol, thiodiglycol, thioglycolic acid, ascorbic and isoascorbic acid. The chain transfer agent can be used in an amount of approx. 0.2 to 3.5 percent by weight based on the monomer weight. The copolymers used in the present invention are water-soluble and can be diluted. They remain in solution indefinitely without significant excretion

of oil content and is able to tan leather or hides without cracking the grain.

For the purpose of tanning hides or skins, the copolymer is dissolved in water at a concentration of approx. 5 to 4-0 percent by weight. The copolymer obviously does not need to be isolated from the aqueous solution in which it is made. Such solutions only need to be regulated to the desired concentration for use in tanning. A salt, such as sodium chloride or sodium sulfate, is introduced into the tanning solution in a concentration of 3 to 8 percent by weight. The tanning liquid is poured into a suitable container, such as the conventional tanning drum, and then the skins are fed into the drum. The weight of the rails in relation to the weight of the liquid is usually determined to thus provide approx. 20 to 25% active tanning agent based on the weight of acid-treated leather and approx. 5 to 15% salt, when. this is used, based on the weight of the leather. The tanning is effected by treating the leather in a drum or container at room temperature up to, but not above 35°C. Usually the temperature is between 28° and 32°C. The drum treatment

in the tanning liquid can be carried out for several hours, as e.g. from 4 to 24 hours.

This tanning can be followed by a mineral tanning, a

vegetable extract tanning, or a synthetic tanning agent.

In the retanning of leather that has previously been mineral tanned, especially chrome tanned or zirconium tanned, or tanned in other ways, the concentration of the copolymer can be from 0.5 to 10 percent by weight in the tanning liquid. Usually no salt is used in this tanning liquid, and the amount of tanning liquid in relation to the partially tanned leather treated with this liquid is of such a magnitude that it provides approx. 1 to 5% of the copolymer based on the weight of the wet chrome treated leather. This means that to provide the 3% Pa leather, one would have to use 200%, based on the weight of the leather, of a liquid containing 1 1/2% of the copolymer.

The tanning agent according to the present invention can be used for the treatment of all types of hides and skins, such as e.g. horsehide, cowhide, goatskin, sheepskin, pigskin, etc. The tanned products are suitable for use in all types of leather, e.g. shoe leather, sole and upper leather, leather for upholstery, suitcase leather, leather for furniture and industrial leather.

To assist the person skilled in the art in the implementation of the present invention, the following working methods are proposed with the help of examples, where parts by weight and percentage by weight are used and the temperature is in °C unless otherwise stated.

l) Three solutions are prepared as follows:

Solution A

312 g aqueous<*> sulfated castor oil (234 g real oil)

I86O ml of deionized water.

Solution B

1200 g methacrylic acid (MAA)

l68 ml aqueous hydroxylamine solution (6.0 g real

hydroxylamine) (H.A.)

Solution G

52 g aqueous hydrogen peroxide (35%) f18 g real H202)

600 ml of deionized water.

Solution A is heated in a glass reaction vessel to 90°C. Solutions B and C are added gradually and simultaneously over a 50 minute period through suitable devices, such as e.g. separatory funnel, to feed the reaction vessel while maintaining the temperature at 89° to 93°C. The mixture is heated for 1 1/2 hours longer at 90°C l- 1°C). It is then cooled, while stirring, to 70° - 75°0. Then 0.1% phenol (based on the product) is added and stirring is continued for a further 15 minutes at 70° - 75°C. The solution of 33 l/3% solid copolymer weighs 4268 g and has a viscosity of 33 poise at 25°G.

(Brookfield LVF viscometer, spindle No. 3 at 12 rpm).

2) Tanning of acid- and salt-treated leather

38 g of acid- and salt-treated calfskin is placed in a bottle. To this is added a tanning solution consisting of: 27 g of tanning material of the 33 l/3% solids (from l) above) 3.8 g NaCl

76 ral water

This bottle is sealed and shaken in a shaker for 24 hours. Then 1.5 g of sodium acetate is added and the bottle is shaken for a further three hours, then the liquid is emptied out. The leather is washed thoroughly with water, degreased with a mixture consisting of 0.3 g of "Texol N" (a commercial sulfated claw oil), 0.08 g of claw oil, and 57 ml of water, this is shaken for an hour, left to dry and finally moistened and mute.

A very fine piece of white leather is obtained, which piece shows very good lightfastness and very good aging properties.

3) Two solutions are prepared:

Solution A

105 ml of water

1.75 6 ammonium persulfate

Solution B

50 g methacrylic acid (MAA)

13 g of aqueous sulfated spermaceti oil (10 g of real oil).

Solution A is heated to 90°C. Solution B is added

to solution A over a 40 minute period. The mixture is stirred for 1 l/2 hours at 90° - 95°C. Then 1.5 g of ammonium hydroxide (28% NHo) is added, followed by stirring for a further 15 minutes at 90° - 95 o C. The mass is stirred while it cools to approx. 70 o0. The product is a 35% solid solution of copolymer. At 25°C and 33% concentration, it has a viscosity of 70 poise.

4) Retanning of chrome leather.

23 g of chrome-tanned calfskin is lined into a bottle. To this is added a tanning solution consisting of: 2.5 g of the 35% solution of tanning agent formed in

3) over

46 ml of water

This is stirred in a shaking machine for 1 l/2 hours. The liquid is then drained off and the resulting leather is thoroughly washed. Finally, it is laid out, dried, moistened and solidified. The leather provided shows excellent fullness and is well bleached, and is much better than chrome leather which is not retanned. The leather also shows excellent lightfastness and aging properties.

5) Three solutions are formed:

Reading A

l60 ml of water

2.0 g hydroxylamine sulfate

26 g aqueous sulfated clove oil (20 g real oil)

Solution B

100 g methacrylic acid (MAA)

Solution C

3.3 g hydrogen peroxide ( 30%)

50 ml of water.

Reading A is heated to S0°C. The readings B and C are then added gradually and at the same time over a 40 minute period while recirculation is carried out. Then quickly add 0.7 g of H202. The mixture is stirred for a further 1 1/2 hours at 90° 95°C. An ammonium hydroxide solution (2 g 28% NH 2 + 4 ml H 2 O) is then added over the course of 1 minute. The mixture our for another 20 minutes at 90° - 95°C

and then, while conversion is in progress, it is reduced to approx. 70°C. The product is a 35% fixed reading of copolymer. At 25°C and 33% concentration it has a viscosity of 40 poise.

6) Re-tanning of zirconium-tanned leather.

41 g of zirconium-tanned calfskin is fed into a bottle. To this is added a tanning solution consisting of: 6.8 g of the 35% reading tanning agent from 5) above, 82 ml of water.

This is shaken for 3 hours. The liquid is tamed out and the leather is thoroughly washed. It is then grease treated with 1.64 g of "Albin oil 300W" (a commercial sulphated claw oil) and 0.41 g of oil in 63 ml of water, finally it is laid out, surface treated, moistened and set. The resulting white leather showed excellent body and color.

7) Three readings were made:

Solution A

190 ml of water

30 ml hydroxylamine solution (1.02 g real H.A.)

26 g aqueous sulfated cod liver oil (20 g real oil)

Solution B

90 g methacrylic acid (MAÅ)

10 g acrylic acid (AA)

Solution C

2.9 g hydrogen peroxide (35%)

50 ml of water.

Solution A is heated to 90°C. Solutions B and G are added simultaneously over a period of 5 minutes.

Then quickly add 0.5 g of HgOg (35%) and the mixture is stirred for a further 1 l/2 hour at 89 - 92 C. Then cooling is carried out to approx. 70°C while stirring takes place. The product is a 30.5% solution of acid copolymer. At 25°C and 33% concentration, it has a viscosity of 35 poise.

8) Tanning of mineral tanned leather

41 g of acid- and salt-treated calfskin is placed in a bottle. To this is added a tanning solution consisting of: 6.9 g of the 30.5% solution of tanning agent formed in 7) above

4.1 g NaCl

82 ml of water.

This is shaken for 18 - 20 hours. The pre-tanned leather is then tanned in the normal way with 9-9 g of basic zirconium sulphate. After tanning, the leather is thoroughly washed and treated with 1.64 g of "Albin oil 300 W" and 0.41 g of clove oil in 63 ml of water. Finally, the leather is laid out, surface treated, moistened and solidified. The leather provided showed excellent fullness and color.

9) Two solutions were made:

Solution A

200 ml of water

13 g aqueous sulfated soybean oil (10 g real oil)

O.25 g of lauroyl peroxide.

Solution B J

50 g methacrylic acid (MAA)

50 ml of water

1.5 g mercaptoethanol.

Solution A is heated to 90°C and solution B is added over a period of 45 minutes. One hour later, a solution of 0.8 g of ammonium persulphate in 7 "l of water is added and the mixture is stirred for 1 hour at 90°C (-1°C).' Cooling is then carried out to 34° - 4-0°C while stirring takes place. Weight of product treated under reduced pressure = 107 g, final copolymer solution weight is 212 g (approximately 28% solids). At 25°C and 33% concentration, it has a viscosity of 34 poise. 10) Retanning of chrome-tanned calfskin with a polymer tanning agent and a vegetable tanning agent. 30 g of a chrome-tanned calfskin is placed in a bottle. To

to this is added a tanning solution consisting of:

1.8 g of the 28% solution of tanning agent from 9) above.

60 ml of water.

This is shaken for 2 hours, then the liquid is emptied and it

the tanned piece is rinsed. The following solution is then added:

1.2 g quebracho powder

60 ml of water.

This is shaken for 2 1/2 hours and the liquid is emptied, then the piece is thoroughly washed and grease treated with 0.6 g of sulphated claw oil

in 45 ml of water, and finally it is laid out, dried, moistened and set. An excellent piece of leather is provided, and this showed a very light color, very good lightfastness, and good fullness and roundness. 11) Acid/sulphated oil copolymer solutions with approx. 30% concentration is provided by repeating the procedure indicated

in 7) with the exception that the sulphated cod liver oil is replaced with

a) sulfated castor oil

b) sulphated claw oil v

c) sulfated spermaceti oil

d) sulfated soybean oil.

Each of the resulting copolymer solutions can be used for tanning, re-tanning or pre-tanning as in any of the processes 2), 4^> 6)> 8) and 10). 12) a) Acid/sulphated oil copolymer solutions of approximately 30% concentration are prepared by repeating the procedure indicated in 7), with the exception that solution B is replaced by a mixture consisting of 75 g of methacrylic acid and 25 g of acrylic acid. b) Part a) is repeated with the exception that the sulphated cod liver oil is replaced with

a) sulfated castor oil

b) sulphated claw oil

c) sulfated spermaceti oil

d) sulfated soybean oil.

Each of the resulting copolymer solutions can

used for tanning, re-tanning or pre-tanning as in any of the processes 2), 4) > 6), 8) and 10).

Claims (3)

1. Tanning agent, characterized in that it comprises a copolymer of a mixture of 80 - 90 weight percent acrylic acid and/or methacrylic acid and 20 - 10 weight percent of an unsaturated sulphation product of an animal or a vegetable oil. 2. Tanning agent according to claim 1, characterized in that it comprises a copolymer of a mixture of 80 - 90 weight percent methacrylic acid and 20 - 10 weight percent of an unsaturated sulphation product of castor oil, clove oil, spermaceti oil, cod liver oil or soybean oil. 3. Tanning agent according to claim 1, characterized in that it comprises a copolymer of a mixture of at least 75 weight percent methacrylic acid and up to 25 weight percent acrylic acid, calculated on the acid component, and 20 - 10 weight percent of an unsaturated sulphation product of claw oil, spermaceti oil, cod liver oil or soybean oil .