JPH0235800B2 - AKURIRUBEESUNOORIGOMAADEHIKAKUORITANNINGUSURUHOHO * GAIHOHONIMOCHIIRURITANNINGUZAISUIYOEKIOYOBIGAIHOHONYOTSUTERITANNINGUSARETAHIKAKU - Google Patents

Description

[Detailed description of the invention]

The leather retanning method is US Patent No. 4150944
In this method, a reaction product obtained by reacting a sulfonation product preformed, for example from diphenyl ether, phenol and fuming sulfuric acid, with, for example, dimethylol urea or formaldehyde, is retanned. used as an agent. It has been found that, instead of reaction products of the type indicated above, very easily available oligomers with at least an equivalent retanning effect can be advantageously used for skin retanning. The invention therefore relates to a method for retanning chrome-tanned, dyed or undyed leather, which method comprises the formula:

2 to 75 repeating units of [formula] rank, formula

2 to 75 repeating units of [formula], (in these formulas, X ₁ is -CN, -COOR ₁ , -
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. an alkoxyalkyl group containing alkoxyalkyl groups) and whose average molecular weight is up to 14000, or

2 to 75 repeating units of [formula] rank, formula

2 to 75 repeating units of [formula] rank, formula

Up to 25 repeating units of [formula] (In these formulas, X ₁ is −CN, −COOR ₁ , −
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. is an alkoxyalkyl group containing Y ₂
is −CONH ₂ , −CH ₂ OH, −OCH ₃ or −OC ₂ H ₅
and Z ₃ is a hydrogen atom, a methyl group or an ethyl group) and whose average molecular weight is up to 14000 is treated as a retanning agent, and the treated skin is emulsified. It consists of fattening and drying and, if appropriate, further dyeing this treated hide before or after emulsion fatliquing. Contains an oligomer as a retanning agent,
Aqueous solutions for carrying out the retanning process, skins retanned by the method of the invention, as well as the use of the oligomers as retanning agents are further objects of the invention. Oligomers having structural units of formulas (1) and (2) and groups of formula -SO ₃ M ₁ (4) (wherein M ₁ is an amine cation, ammonium cation or alkali metal cation) are themselves They are known and are described, for example, in US Pat. No. 3,646,099 as conductive and surfactant agents. Constituent unit (1)
Oligomers containing structural units of formula (3) in addition to (2) and (2) are likewise described in US Pat. No. 2,893,977 as components of resin compositions with good adhesive properties. In the above two patent specifications, oligomers are made in the presence of sulfite or bisulfite;
Although in some cases they have a group of formula (4),
In other cases this is not the case. Reports of analytical studies have shown that oligomers precipitated from their aqueous solutions after their known preparation in the presence of sulfites or bisulfites, for example by addition of strong acids such as hydrochloric acid, contain groups of formula (4). It is said that it does not contain it at all or only contains traces of it. It must therefore be assumed that after the preparation of the oligomer in aqueous solution, the sulfite or bisulfite is present alone or at least primarily as a mixed component and not as a group in the oligomer in the form of formula (4). It won't happen. Oligomers precipitated with hydrochloric acid produce the same results as oligomers that are not precipitated when used as retanning agents, so
The presence or absence of a group of formula (4) is not a critical characteristic of the oligomer used in the practice of this invention. However, the oligomers used in the retanning process of the present invention do not need to be precipitated before their use. The essential features of the oligomer of the present invention are formulas (1) and (2).
and possibly the presence of the structural unit (3), with a relatively low average molecular weight of at most 14,000, in particular 3,000 to 12,000,
Preferably 3000-10000, most preferably 4000-
It is 9000. The relatively low molecular weight of the oligomers of the present invention compared to the high molecular weight polymers used in the plastics industry, for example for the production of synthetic fibers, varies depending on the use of sulfite or bisulfite in the oligomer production. Preferred oligomers used as retanning agents in the process of the invention because of their average molecular weight have formulas (1) and (2) each of 2 to 75, preferably 5
~40, most preferably 10-25 building blocks and formulas
It contains 0 to 25, preferably 0 to 10, most preferably 0 to 5 structural units of (3). Suitable oligomers for their use as retanning agents include formula (2) and optionally
In addition to containing the structural unit represented by (3), the formula

[Formula] (In the formula, X ₂ is -CN, -COOR ₄ , -OOCR ₅ or -CONHR ₆ , R ₄ is a C _1-4 -alkyl group,
C _1-4 - hydroxyalkyl group or methoxyalkyl group with a total of at most 4 carbon atoms;
_R5 is a methyl group or an ethyl group, and _R6 is _C1-8
-alkyl group or C _1-2 -hydroxyalkyl group, and Z ₁ has the meaning defined above), and in particular of the formula

[Formula] (In the formula, X ₃ is −CN, −COOCH ₃ , −COOC ₂ H ₅ , −
COOC ₂ H ₄ OH, − COOC ₃ H ₆ OH, −
COOC ₂ H ₄ OCH ₃ , −OOCCH ₃ , −CONHCH ₃ , −
CONHC ₂ H ₅ , -CONHCH ₂ OH, -CONHC ₃ H ₇ or -CONHC ₈ H ₁₇ and Z ₁ has the meaning given above). Oligomers particularly suitable for use as retanning agents have the formula

【formula】

[formula] and in some cases

[Formula] and −SO ₃ M ₃ (41) (X ₄ in these formulas is −CN, −COOCH ₃ , −
COOC ₂ H ₅ , −COOC ₂ H ₄ OH, −COOC ₃ H ₆ OH, −
OOCCH ₃ , −OOCC ₂ H ₅ , −CONHCH ₃ , −
CONHC ₂ H ₅ , −CONHC ₃ H ₇ and −
CONHC ₈ H ₁₇ and Y ₃ is −COOH or −
COOM ₄ , Y ₄ is −CONH ₂ , −CH ₂ OH or −OCH ₃ , each of M ₃ and M ₄ is a sodium cation, potassium cation or ammonium cation, and Z ₄ , Z ₅ and Z Each of ₆ is a hydrogen atom or a methyl group) Contains structural units represented by formulas (1.4), (2.2), and (3.2) and a group represented by formula (4.2). Preferred oligomers as retanning agents have the formula

【formula】

[expression] and in some cases

Contains a structural unit represented by [Formula] and -SO ₃ Na (4.2). The production of the known oligomers is carried out by methods known per se, for example US Pat.
carried out by the method described in No. 3893977,
formula

【formula】

[Formula] and and depending on the case

[Formula] (wherein X ₁ , Y ₁ , Y ₂ , Z ₁ , Z ₂ and Z ₃ have the meanings given above) are reacted, in which case the compound is reacted in an aqueous medium. A compound of the formula SO ₃ (M ₁ ) ₂ (8) or HSO ₃ M ₁ (9) (in which M ₁ has the meaning given above) is always present and optionally polymerized. The reaction is carried out in the presence of a catalyst at a maximum temperature of 70°C and the aqueous reaction mixture is brought to a pH value of 5 to 7 with a base of the formula M ₂ OH (10) in which M ₂ has the meaning given above. Manufactured by adjusting. A preferred procedure is to convert each of the starting monomers (5), (6) and optionally (7) into compounds of formula (8) or (9).
2 to 2 per mole or equivalent of starting compound of
75, preferably from 5 to 40 and most preferably from 10 to
25 moles are loaded into the reactor, usually first adding component (5) to avoid homopolymerization of the more reactive component (6), then component (6) and optionally Add component (7) and then add a small amount to the monomer [for example, 1/20 to 1/20 of the total amount of the starting compounds of formulas (5) to (9)].
1/5] of a polymerization catalyst such as azoisobutyronitrile or preferably a peroxide such as benzoyl peroxide or especially ammonium persulfate (i.e. a compound of the formula (NH ₄ ) ₂ S ₂ O _{8 )} . is added to the aqueous solution of the starting compound in small portions, e.g. 8 to 12 portions, or continuously in 5 to 12 portions.
The addition was carried out over a period of 8 hours, thus starting the exothermic polymerization reaction. Conveniently the reaction mixture is cooled so that the temperature does not exceed 70°C, preferably 40°C. 50~55℃
In the preferred temperature range of , polymerization takes place from 4 to
Usually completed in 6 hours. Upon completion of the polymerization, the reaction mixture is heated by addition of a compound of formula (10) with cooling not exceeding the temperature indicated above, preferably about 5 to 7
Adjustment to a convenient PH value of 6.1 to 6.3 results in an aqueous gel-like solution of the copolymer. After addition of the compound of formula (10), the reaction is maintained at 60-80° C. for 6-10 hours, if necessary under reduced pressure (-10 to -1 bar), in order to completely remove the unpolymerized starting compound. can do. Thus, for example, terpolymers containing units of the formulas (1.2), (2.1), (3.1) and optionally groups of (4.1) can be prepared using starting compounds of the formula (8) or (9), such as sodium sulfite. , potassium or ammonium or sodium bisulfite, potassium or ammonium, monomers of formula (5) such as acrylonitrile, methacrylonitrile, ethyl acrylonitrile, methyl acrylate, ethyl acrylate, methyl methacrylate, ethyl methacrylate, hydroxyethyl acrylate, hydroxyethyl methacrylate, hydroxy Propyl acrylate, hydroxypropyl methacrylate,
Methoxyethyl acrylate, vinyl acetate, vinyl propionate, N-methacrylamide, N-ethylacrylamide, N-methylolacrylamide, N-isopropylacrylamide or N-isooctylacrylamide, formula (6)
monomers such as acrylic acid, methacrylic acid or α-ethyl acrylic acid and monomers of formula (7) such as acrylamide, methacrylamide, vinyl methyl ether or allyl alcohol are copolymerized with each other and then a base of formula (10) such as water Made by neutralizing the reaction mixture with sodium oxide, potassium hydroxide or ammonia. When retanning chrome-tanned hides by the method of the invention, the procedure according to known methods conveniently involves treating the hide with an aqueous solution containing at least one oligomer of the type mentioned above and then tanning the hide. The procedure is that the material is rinsed with water and then generally emulsified and dried. If the skin to be retanned has not been dyed, then if desired it can be dyed before emulsification. Usually from 100 to 200, preferably from 150 to 200 parts by weight of water and from 2 to 50, preferably from 5 to 10 parts by weight, based on the solids content of at least one oligomer of the type indicated, are used per 100 parts of skin. However, the aqueous solution for carrying out this retanning method uses oligomer 1 as a retanning agent.
-10, most preferably 2 to 5 parts by weight. This skin is usually heated at 10 to 50℃, preferably 10 to 30℃.
Treated with aqueous solution for ~4 hours. If undyed leather is dyed with a commercially available leather dye, such as an acid or metal complex dye, the dye is conveniently added to the tanning liquor after retanning. In this case, rinsing with water is therefore dispensed with. If, on the other hand, the skin is not to be dyed, then it is expedient to rinse the skin for a short time, for example 15 to 30 minutes, with water at a temperature of 10 to 50°C, preferably 10 to 30°C. The retanned, dyed or undyed hides are then emulsified with a conventional, preferably lightfast, emulsifying fatliquoring agent derived from, for example, sulfonated sperm whale oil or cow leg oil. This milky fat is produced at a temperature of about 30 to 80℃, for example.
It lasts between 30 and 90 minutes. Approximately 30 to 80 pieces of this skin
After drying in the temperature range of °C, it has excellent light fastness, fine, dense, smooth skin texture and particularly soft touch. If not dyed, a very blue pale skin is additionally obtained. The strong bleaching effect obtained in particular on chrome-tanned leather by this retanning method is particularly advantageous. In addition, the oligomers used as retanning agents in the process of the invention have excellent compatibility with other commercially available tanning agents, so that these latter can be used in combination with the oligomers of the invention. can. Any type of skin, including wet blue leather such as calfskin, cowskin, goatskin or sheepskin, is suitable for use as the chrome-tanned hide in the present invention, and this chrome-tanned hide is usually Before retanning in the process, it is neutralized, for example with formate or bicarbonate. The percentages and parts in the following examples are by weight. Example of producing oligomers Example A A solution containing 165.3 parts (2.29 mol) of acrylic acid, 122.0 parts (2.29 mol) of acrylonitrile, and 39.8 parts (0.153 mol) of a 40% aqueous sodium bisulfite solution in 280 parts of deionized water was heated at 29°C. Heat to.
Add 1% ammonium persulfate aqueous solution 0.96 to this solution.
10 portions are added every 15 minutes (ie a total of 9.6 parts within 2.5 hours), with the reaction mixture being cooled such that the temperature after each addition is a maximum of 34°C. The white emulsion thus obtained is then diluted with 96 parts of deionized water. This reaction mixture was then diluted with 20
℃ and keep at this temperature for 7 hours. After this time, the reaction mixture is kept under vacuum and an inert nitrogen atmosphere for 2 hours to remove unreacted acrylonitrile. The emulsion is then brought to a pH value of 6 with 287.3 parts (2.15 mol) of 30% aqueous sodium hydroxide solution, the reaction mixture being cooled so that its temperature does not rise above 40.degree. After cooling the reaction mixture to 20°C a bright yellow, gel-like, clear aqueous solution 1000
34% of oligomers having about 15 units of formula (1.4), about 15 units of formula (2.2) and traces of groups of formula -SO ₃ Na. Example B Do the same as Example A, but with acrylic acid
A solution of 185.9 parts (2.58 moles), 64.7 parts (1.22 moles) of acrylonitrile and 19.8 parts (0.076 moles) of 40% sodium bisulfite solution in 69.8 parts of water is used, and to this solution 19.8 parts of ammonium persulfate is added to 10
Add in batches, dilute with 96 parts of water, and then add 344 parts (2.58 mol) of sodium hydroxide solution. 1000 parts of a bright yellow, gel-like clear aqueous solution is obtained,
It contains 31% oligomer, which has about 16 units of formula (1.4), about 34 units of formula (2.2) and traces of groups of formula -SO ₃ Na. Example C Do the same as Example A, but with acrylic acid
185 parts (2.56 mol), 34 parts (0.64 mol) of acrylonitrile
Using a solution containing 55.6 parts (0.214 mol) of sodium bisulfite solution in 257 parts of water, 10.7 parts of ammonium persulfate was added in 10 portions to this solution, diluted with 116.4 parts of water, and then sodium hydroxide solution. Add 341.3 parts (2.56 moles). 1000 parts of a bright yellow, gel-like, clear aqueous solution is obtained, containing 28% of oligomers containing about 3 units of formula (1.4) and about 12 units of formula (2.2) and of the formula -SO ₃ Contains traces of Na groups. Example D Do the same as Example A, but with acrylic acid
Ammonium persulfate Add 11.4 parts of the solution in 10 portions, dilute with 92.9 parts of water, and then add 256 parts (1.92 mol) of sodium hydroxide solution. bright yellow,
1000 parts of a gel-like clear aqueous solution is obtained, which contains 34% oligomer, which has the formula (3.2)
It has about 3 constituent units of formula (1.4), about 15 constituent units of formula (2.2), and trace amounts of groups of formula -SO ₃ Na. Example E Do the same as Example A, but with acrylic acid
Using an emulsion containing 211 parts (2.92 mol) of vinyl acetate, 141.5 parts (1.64 mol) of vinyl acetate and 43 parts (0.165 mol) of 40% sodium bisulfite solution in 80 ml of water, this solution was added at 50°C to 25 ml of water. Add a total of 1.5 parts of dissolved ammonium persulfate in 10 portions to 155 parts of water.
After diluting with 320 parts of sodium hydroxide solution (2.4 parts
mol). Bright yellow, gel-like aqueous solution
1000 parts are obtained, which contains 40% oligomers,
The oligomer has the formula (1.3) (X ₄ in this formula is −
COOCH ₃ , Z ₄ means a hydrogen atom), about 10 constituent units of formula (2.2), about 18 constituent units of formula (2.2) and the formula -
It has traces of SO ₃ Na groups. Example F 171 parts of water are placed in a reactor, first 74.9 parts (1.41 mol) of acrylonitrile, then 101.7 parts (1.41 mol) of acrylic acid, and finally 24.3 parts (0.93 mol) of a 40% aqueous sodium bisulfite solution. A solution of 0.6 parts of ammonium persulfate in 6 parts of water is added to the reaction mixture over a period of 5 to 8 hours, at a temperature of 45
Do not exceed ℃. When this catalyst addition is complete, 60 parts of water are added and the reaction mixture is maintained at 75°C for 5 hours. Subsequently, 146 parts of a 30% aqueous sodium hydroxide solution was added to the reaction mixture for about 1.5 hours at a temperature of 50°C.
Add so as not to exceed ℃. The reaction mixture was then heated to reflux temperature (98 to 100 °C) and −0.8 to −
maintained at reflux temperature for approximately 8 hours under reduced pressure of 1.0 bar;
If the unreacted acrylonitrile in the sample of the reaction mixture is
Continue until the concentration is less than 100ppm. The reaction mixture is then cooled to 20 DEG C. and the pH value is brought to 6.1-6.3 by adding thereto in small portions a total of about 22 parts of 30% aqueous sodium hydroxide solution. 600 parts of a clear, slightly yellow solution are thus obtained, containing 33-34% of oligomers of the formula (1.4)
and (2.2) each have 25 to 30 constituent units. Example G Do the same as Example A, but with acrylic acid
128.4 parts (1.78 mol), 144.2 parts (1 mol) of hydroxypropyl methacrylate and 47.4 parts (0.1 mol) of a 25% aqueous potassium bisulfite solution were added to water.
Using the solution contained in 100 parts, add a total of 10 parts of ammonium persulfate to this solution at 60°C in 10 parts,
Sodium hydroxide solution after dilution with 351.5 parts of water
Add 218.5 parts (1.63 moles). 1000 parts of a slightly yellow, gel-like, transparent aqueous solution were obtained containing 31% of oligomers of the formula (1.3), where X ₄ is -COOC ₃ H ₆ OH and Z ₄ is a methyl group. It has about 12 constituent units of formula (2.2), about 22 constituent units of formula (2.2), and trace amounts of a group of formula -SO ₃ Na. Example H The same procedure as Example A is carried out, except that 73.6 parts (0.51 mol) of acrylic acid-2-ethoxyethyl ester, 93.8 parts (1.30 mol) of acrylic acid and 25%
Using a solution containing 33.6 parts (0.07 mol) of potassium bisulfite aqueous solution in 60 parts of water, a total of 5 parts of ammonium persulfate solution was added to this solution in 5 portions at 60°C, diluted with 565.8 parts of water, and then hydroxylated. Add 168.2 parts (1.26 moles) of sodium solution. clear aqueous solution
1000 parts are obtained, which contains 20% oligomers,
The oligomer has the formula (1) (X ₁ in the formula is −COOR ₁
, R ₁ is a 2-ethoxyethyl group, Z ₁ is a hydrogen atom), about 7.3 constituent units of formula (2.2), about 18.5 constituent units of formula (2.2), and a trace amount of a group of formula -SO ₃ Na. There is. Example I Do the same as Example A, but with acrylic acid
130.7 parts (1.81 mol), acrylonitrile 120.3 parts (2.26 mol), allyl alcohol 26.3 parts (0.40 mol)
and 72.6 parts (0.15 mol) of a 25% potassium hydrogen sulfite aqueous solution in 283.5 parts of water, and a total of 37.8 parts of ammonium persulfate solution was added to this solution in 5 parts.
Add in batches, dilute with 87 parts of water and then mix with 241.8 parts (1.81 mol) of sodium hydroxide solution. 1000 parts of a clear aqueous solution in the form of a bright yellow gel are obtained, containing 32% of oligomers of the composition of formula (3.1), where Y ₄ is -CH ₂ OH and Z ₆ is a hydrogen atom. unit about 2.6, about 15 constituent units of formula (1.4), about 12 constituent units of formula (2.2) and formula −
It has traces of SO ₃ Na groups. Example J Do the same as Example A, but with acrylic acid
133 parts (1.84 moles), 149.4 parts (1.03 moles) of methyl acrylic acid hydroxypropyl ester and 25
A solution containing 49 parts (0.10 mol) of potassium bisulfite aqueous solution in 98.4 parts of water was used, and 10 parts of ammonium persulfate solution containing a total of 12.2 parts of ammonium persulfate solution was added to this solution at 40°C.
Add in portions, dilute with 461.7 parts of water, and mix with 96.3 parts (1.7 mol) of a 30% ammonia aqueous solution.
1000 parts of a clear aqueous solution in the form of a yellowish gel are thus obtained, containing 31% of oligomers of the formula (1.3), where X ₄ is -COOC ₃ H ₆ OH, Z ₄
means a methyl group), about 10 structural units of the formula (2.1) (in the formula, Z ₅ is a hydrogen atom, Y ₃ is -COOM ₄ ,
M ₄ means ammonium cation) and has trace amounts of groups of the formula -SO ₃ NH ₄ . Application Examples Example 1 100 parts of calf skin, neutralized and chrome-tanned in the usual manner and manner, are mixed with 200 parts of water and 5 parts, calculated based on the solids content of the oligomer according to Example A above, for 1.5 hours.
Perform retanning at 30℃. After rinsing briefly, the retanned skin is conventionally emulsified with 4 to 6 parts of a lightfast emulsion fatliquor derived from sulfonated pine whale oil and dried. This results in a fine-grained leather with a bright color, excellent lightfastness and a soft, rich feel. The same result is obtained if, instead of 5 parts of the oligomer according to Example A, 5 parts of the oligomer according to Example F are used. Example 2 100 parts of chrome-tanned sheep skin and 200 parts of water at 40℃
Soak in the water. Now add 10 parts to the dyebath, calculated on the solids content of the oligomer according to Example B, and treat with this retanning liquor at 40° C. for 2 hours. After rinsing, the treated hides are emulsified with about 5 parts of a conventional emulsifying fatliquor and then dried. A rich, supple skin is obtained, which is dense and fine-grained. The same result is obtained when, instead of 10 parts of the oligomer according to Example B, 10 parts of the oligomer according to Example C are used. Example 3 In 200 parts of a dyeing liquor by a known method in a bath,
Chrome-tanned folded cowhide is neutralized so that its pH value remains below 4 at the cut surface. Subsequently, 6 parts, calculated by solid weight, of the terpolymer according to Example D are added to this bath and the neutralized skin is treated for 2 hours at 45°C. The formula below A new dye liquor (300 parts) containing 1 part of the dye represented by
Dye this skin for 30 minutes at 60℃ in a room. After acidifying with 1 part of 85% formic acid for 30 minutes at 50°C, the exhausted dyebath is fed with 3 parts of sulfated cow leg oil and the cowhide is fatliquified at 60°C for 60 minutes. Wring out the skin and dry. After being roasted, the skin has a rich, soft texture, a dense, fine-grained skin, and a deep, uniform dyeing. Example G instead of 6 parts of terpolymer according to Example D
Similar results are obtained when using 6 parts of a copolymer according to Example H, 6 parts of a copolymer according to Example H, 6 parts of a terpolymer according to Example I or 6 parts of a copolymer according to Example J.

Claims (1)

[Claims] 1. A method for retanning chrome-tanned, dyed or undyed leather, comprising:
As a retanning agent, 2 to 75 repeating units of the formula [formula], 2 to 75 repeating units of the formula [formula], (in these formulas, X ₁ is −CN, −COOR ₁ , −
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ each represent a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. treating said skin with an aqueous solution containing an oligomer containing alkoxyalkyl groups) and having an average molecular weight of up to 14,000, emulsifying the treated skin and drying it, if appropriate. A method characterized in that the treated skin is further dyed before or after emulsification. 2. The method according to claim 1, wherein an oligomer containing 5 to 40 repeating units each represented by formulas (1) and (2) is used as a retanning agent. 3. The method according to claim 2, wherein an oligomer containing 10 to 25 repeating units each represented by formulas (1) and (2) is used as a retanning agent. 4 The repeating unit of formula ( _{1 )} is _{[ Formula ]} (wherein _,
C _1-4 - hydroxyalkyl group or methoxyalkyl group with a total of at most 4 carbon atoms;
R ₅ is a methyl group or an ethyl group, and R ₆ is C _1-8
-alkyl group or C _1-2 -hydroxyalkyl group, and Z ₁ has the meaning defined in claim 1) is used as a retanning agent in claim 1.
The method according to any one of Items 3 to 3. 5 The repeating unit of formula (1.1) is
[Formula] (wherein, X ₃ is −CN, −COOCH ₃ , −COOC ₂ H ₅ ,
−COOC ₂ H ₄ OH, −COOC ₃ H ₆ OH, −
COOC ₂ H ₄ OCH ₃ , −OOCCH ₃ , −CONHCH ₃ , −
CONHC ₂ H ₅ , -CONHCH ₂ OH, -CONHC ₃ H ₇ or -CONHC ₈ H ₁₇ and Z ₁ has the meaning defined in claim 1) as a retanning agent. The method according to claim 4 for use as a method. 6 The repeating unit of formula (1) is represented by the formula [formula], and the repeating unit of formula (2) is represented by the formula [formula]. (In these formulas, X ₄ is −CN, −COOCH ₃ , −
COOC ₂ H ₅ , −COOC ₂ H ₄ OH, −COOC ₃ H ₆ OH, −
OOCCH ₃ , −OOCC ₂ H ₅ , −CONHCH ₃ , −
CONHC ₂ H ₅ , −CONHC ₃ H ₇ and −
CONHC ₈ H ₁₇ and Y ₃ is −COOH or −
COOM ₄ , M ₄ is a sodium cation, potassium cation or ammonium cation, and Z ₄ and Z ₅ are each a hydrogen atom or a methyl group) oligomer as a retanning agent The method according to any of paragraph 5. 7 A copolymer containing a repeating unit of formula (1.3) represented by formula [formula] and a repeating unit of formula (2.1) represented by formula [formula] is used as a retanning agent according to claim 6 the method of. 8. In a method for retanning chrome-tanned, dyed or undyed leather,
As a retanning agent, 2 to 75 repeating units of formula [formula], 2 to 75 repeating units of formula [formula], up to 25 repeating units of formula [formula] (in these formulas, X ₁ is −CN, −COOR ₁ , −
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. is an alkoxyalkyl group containing Y ₂
is −CONH ₂ , −CH ₂ OH, −OCH ₃ or −OC ₂ H ₅
and Z ₃ is a hydrogen atom, a methyl group or an ethyl group) and whose average molecular weight is up to 14,000, treating said skin with an aqueous solution containing an oligomer, and emulsifying the treated skin, and further dyeing this treated hide before or after drying it and, if appropriate, emulsifying it. 9. The method of claim 8, wherein the oligomer contains up to 10 repeating units of formula (3). 10. The method of claim 9, wherein the oligomer contains up to 5 repeating units of formula (3). 11 The repeating unit of formula (3) is [formula] (wherein Y ₄ is -CONH ₂ , -CH ₂ OH or -
OCH ₃ and Z ₆ is a hydrogen atom or a methyl group) Claims 8 to 1
The method according to any of item 0. 12. The method according to claim 11, wherein the repeating unit of formula (3.1) is [formula]. 13 A terpolymer containing a repeating unit of formula (1.3) represented by formula [formula], a repeating unit of formula (2.1) represented by formula [formula], and a repeating unit of formula (3.1) represented by formula [formula]. The method according to claim 8 for use as a retanning agent. 14. The method according to any one of claims 1 to 7, wherein 2 to 50 parts by weight of the oligomer is used as a retanning agent based on solids content per 100 parts by weight of skin. 15 Claim 1 in which 5 to 10 parts by weight of oligomer is used as a retanning agent per 100 parts by weight of skin
The method described in Section 4. 16. A method according to any one of claims 1 to 7, which comprises treating the skin with an aqueous solution containing an oligomer as a retanning agent at 10 to 50°C for 1 to 4 hours. 17. Treating hides, dyed or not, with an aqueous solution containing an oligomer as a retanning agent, rinsing the hides so treated,
8. A method according to any one of claims 1 to 7, comprising emulsifying and drying. 18. Claim 1 consisting of treating undyed leather with an aqueous solution containing an oligomer as a retanning agent, dyeing the skin so treated, emulsifying it and drying it. The method according to any one of Items 7 to 7. 19. The method according to any one of claims 8 to 13, wherein 2 to 50 parts by weight of the oligomer is used as a retanning agent based on solids content per 100 parts by weight of skin. 20 Claim 1 in which 5 to 10 parts by weight of oligomer is used as a retanning agent per 100 parts by weight of skin
The method described in Section 9. 21 Claims 8 to 1 consist of treating the skin with an aqueous solution containing an oligomer as a retanning agent at 10 to 50°C for 1 to 4 hours.
The method described in any of Section 3. 22 treating the hide, dyed or not, with an aqueous solution containing the oligomer as a retanning agent and rinsing the hide so treated;
14. A method according to any of claims 8 to 13, comprising emulsifying and drying. 23. Claim 8, consisting of treating undyed leather with an aqueous solution containing an oligomer as a retanning agent, dyeing the skin so treated, emulsifying it and drying it. The method according to any one of Items 1 to 13. 24 The repeating unit of formula [formula] is 2 to 75 units, the repeating unit of formula [formula] is 2 to 75 units, (in these formulas, X ₁ is -CN, -COOR ₁ , -
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. An aqueous solution of a retanning agent containing 1 to 10 weight percent of an oligomer containing alkoxyalkyl groups and having an average molecular weight of up to 14,000. 25. The aqueous solution according to claim 24, containing 2 to 5% by weight of oligomer. 26 Repeating units of formula [formula] from 2 to 75 units, repeating units of formula [formula] from 2 to 75 units, repeating units of formula [formula] up to 25 units (In these formulas, X ₁ is −CN, −COOR ₁ ，−
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. is an alkoxyalkyl group containing Y ₂
is −CONH ₂ , −CH ₂ OH, −OCH ₃ or −OC ₂ H ₅
and Z ₃ is a hydrogen atom, a methyl group or an ethyl group) and has an average molecular weight of up to 14,000. 27. The aqueous solution according to claim 26, containing 2 to 5% by weight of oligomer. 28 The repeating unit of formula [formula] is 2 to 75 units, the repeating unit of formula [formula] is 2 to 75 units, (in these formulas, X ₁ is -CN, -COOR ₁ , -
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. Leather retanned using an aqueous solution containing an oligomer (containing alkoxyalkyl groups) whose average molecular weight is up to 14,000. 29 Repeating units of formula [formula] from 2 to 75 units, repeating units of formula [formula] from 2 to 75 units, repeating units of formula [formula] up to 25 units (In these formulas, X ₁ is −CN, −COOR ₁ ，−
OOCR ₂ or −CONHR ₃ and Y ₁ is −COOH
or −COOM ₂ , Z ₁ and Z ₂ are each a hydrogen atom, methyl group or ethyl group, and M ₂
is an amine cation, an ammonium cation or an alkali metal cation, and R ₁ , R ₂ and R ₃ are each a C _1-8 -alkyl group, a C _1-8 -hydroxyalkyl group or a total of up to 8 carbon atoms. is an alkoxyalkyl group containing Y ₂
is −CONH ₂ , −CH ₂ OH, −OCH ₃ or −OC ₂ H ₅
and Z ₃ is a hydrogen atom, a methyl group or an ethyl group) and whose average molecular weight is up to 14,000.