Method of preserving hides and skins

Abstract

A method for preserving hides, skins and pelts prior to tanning, without salt-curing. The preliminary steps of washing, fleshing, liming, unhairing, deliming and bating the hides are followed by the steps of fatliquoring, pickling and drying. The method avoids the environmental damage cause by salt-curing. The treated hides are dry, flexible and readily rehydrated for further processing.

Description

technical field

[0001] The present invention relates to the preservation of hides, skins and pelts, and in particular to a method of preservation prior to tanning. Background technique

[0002] The method of making leather from hides and hides has changed relatively little over the years, and the many steps that make up the method are well known in the industry. Generally, there are preliminary steps of preserving the hides and making them ready for tanning, followed by tanning and further processing steps. A typical sequence of steps in the pre-tanning part of the process is salting (sodium chloride), soaking and washing, fleshing, liming, dehairing, softening and pickling.

[0003] The salting of the hides, which is carried out as a first step, is carried out by immersing the hides in a brine solution, by wet curing or by dry curing. The purpose of salting is to retard spoilage before proceeding to the rest of the tanning process. In North America and many other parts o...

Examples

Embodiment 1

[0039] The hides are processed by fatliquoring with anionic fatliquor at pH 8 and 30°C for 90 minutes, then pickled, squeezed, dried by spin drying and strained. The following combinations of weight percent of anionic fatliquor and type of pickling solution were used.

[0040] sample number

Weight % Anionic Fatliquor

pickling solution

1

2

standard acid

2

5

standard acid

3

5

Diacid

4

10

standard acid

5

10

Diacid

6

15

standard acid

7

2

Standard Acids with Mixed Salts 1

8

2

Diacids with mixed salts 2

9

5

Standard Acids with Mixed Salts 1

10

5

Diacids with mixed salts 2

11

10

Standard Acids with Mixed Salts 1

12

10

Diacids with mixed salts 2

13

15

Standard Acids with Mixed Salts 1

[0041] 1 3.5% by w...

Embodiment 2

[0044]The hides are processed by pickling followed by fatliquor with cationic fatliquor at pH 2 and 25°C for 90 minutes, then squeezed, dried by spin-drying and strained. The following combinations of weight percent cationic fatliquor and type of pickling solution were used.

[0045] sample number

% by weight cationic fatliquor

pickling solution

1

5

standard acid

2

5

Diacid

3

10

standard acid

4

10

Diacid

5

5

Standard Acids with Mixed Salts 1

6

5

Diacids with mixed salts 2

7

10

Standard Acids with Mixed Salts 1

8

10

Diacids with mixed salts 2

[0046] 1 3.5% by weight sodium chloride, 3.5% by weight potassium chloride, 1% by weight formic acid, 1% by weight sulfuric acid

[0047] 2 3.5% by weight sodium chloride, 3.5% by weight potassium chloride, 2% by weight formic acid, 2% by weight sulfuric ...

Embodiment 3

[0049] The hides were prepared as in Example 1, except that after the flushing step, the hides were solvent-dried, then squeezed, and dried by spin-drying, and finally attenuated. Organic solvents are used at full or half strength (meaning 50% dilution with water). The following combinations of drying parameters were used.

[0050] sample number

technical field

[0001] The present invention relates to the preservation of hides, skins and pelts, and in particular to a method of preservation prior to tanning. Background technique

[0002] The method of making leather from hides and hides has changed relatively little over the years, and the many steps that make up the method are well known in the industry. Generally, there are preliminary steps of preserving the hides and making them ready for tanning, followed by tanning and further processing steps. A typical sequence of steps in the pre-tanning part of the process is salting (sodium chloride), soaking and washing, fleshing, liming, dehairing, softening and pickling.

[0003] The salting of the hides, which is carried out as a first step, is carried out by immersing the hides in a brine solution, by wet curing or by dry curing. The purpose of salting is to retard spoilage before proceeding to the rest of the tanning process. In North America and many other parts o...

Examples

Embodiment 1

[0039] The hides are processed by fatliquoring with anionic fatliquor at pH 8 and 30°C for 90 minutes, then pickled, squeezed, dried by spin drying and strained. The following combinations of weight percent of anionic fatliquor and type of pickling solution were used.

[0040] sample number

Weight % Anionic Fatliquor

pickling solution

1

2

standard acid

2

5

standard acid

3

5

Diacid

4

10

standard acid

5

10

Diacid

6

15

standard acid

7

2

Standard Acids with Mixed Salts 1

8

2

Diacids with mixed salts 2

9

5

Standard Acids with Mixed Salts 1

10

5

Diacids with mixed salts 2

11

10

Standard Acids with Mixed Salts 1

12

10

Diacids with mixed salts 2

13

15

Standard Acids with Mixed Salts 1

[0041] 1 3.5% by w...

Embodiment 2

[0044]The hides are processed by pickling followed by fatliquor with cationic fatliquor at pH 2 and 25°C for 90 minutes, then squeezed, dried by spin-drying and strained. The following combinations of weight percent cationic fatliquor and type of pickling solution were used.

[0045] sample number

% by weight cationic fatliquor

pickling solution

1

5

standard acid

2

5

Diacid

3

10

standard acid

4

10

Diacid

5

5

Standard Acids with Mixed Salts 1

6

5

Diacids with mixed salts 2

7

10

Standard Acids with Mixed Salts 1

8

10

Diacids with mixed salts 2

[0046] 1 3.5% by weight sodium chloride, 3.5% by weight potassium chloride, 1% by weight formic acid, 1% by weight sulfuric acid

[0047] 2 3.5% by weight sodium chloride, 3.5% by weight potassium chloride, 2% by weight formic acid, 2% by weight sulfuric ...

Embodiment 3

[0049] The hides were prepared as in Example 1, except that after the flushing step, the hides were solvent-dried, then squeezed, and dried by spin-drying, and finally attenuated. Organic solvents are used at full or half strength (meaning 50% dilution with water). The following combinations of drying parameters were used.

[0050] sample number