DD133099B1 - METHOD OF DESIGNING LEATHER AND LEATHER MATERIALS - Google Patents

Description

Field of application of the invention

The invention relates to a method for decorating leather or synthetic leather exchange materials with crosslinkable copolymer which substantially improves the utility properties of articles made from these materials.

Characteristic of the known technical solutions

It is known to produce polymers based on acrylic or methacrylic acid esters and other ethylenically unsaturated, polymerizable compounds which are present in side chains of these

Polymers containing, functional groups, such as. 3. carboxyl, hydroxyl, amide, substitierte amide, acetylacetonate and epoxy groups by the addition of suitable polyfunctional Veroindungen such as polyhydric epoxy de, melamine resins, polyfunctional isocyanates undergo crosslinking reactions (Spoor, German colors magazine 22; 7 (1968), p 3o7 to 312).

In some cases, such as B. in the use of Alkoxyalkylacrylamiden or -methacrylamiden or the simultaneous use of epoxydgruppenhaltigen and carboxygruppenhaltisen monomers crosslinking is possible without the addition of such substances (Spoor, German Coloring Book 22, 7 (1968), p 3o7 to 312). The thermal load required for the course of the crosslinking reaction varies depending on the reactivity of the components and the frequently used catalysts in the conducting regions

For example, baking at temperatures well above 100 ° C. is sometimes necessary, while on the other hand, reactive systems, eg polymers and polyisocyanates containing hydroxyl groups, can undergo crosslinking reactions even at room temperature or at slightly elevated temperatures.

Crosslinkable polymers are found in the form of solutions, dispersions, solvent-free systems, for example, corresponding oligomers, fusible, reactive powders, and the like. a. in the textile industry or paint and Anstrichomittelindustrie extended use.

In particular, in the use of so-called soft or hard points of the monomers, such as higher acrylic acid on the one hand and styrene, acrylonitrile or Methylinethacrylaΐ on the other hand, always critical relationship between elasticity and hardness can be made cheaper by building networked structures. Insolubility and low swellability in organic solvents u. Also in water is a further advantage, Further. Regarding. The dressing of leather known polymers which are composed essentially of acrylic acid esters and modified depending on the properties to be achieved with other, in particular the hardness of the film favoring monomers

(Ulimann's Encyclopedia of Industrial Chemistry, 3 * Edition, Vol. 14 (1963) pp. 272 to 273). Suitably come for the dressing of leather generally much softer adjusted polymers characterized z. B. by the higher glass transition temperature, for use as for the purposes of the paint and coatings industry.

Also, in the case of leather coating, it is difficult to meet the high demands placed on the leather in terms of mechanical stress z. As crease resistance and necessary urine to meet.

Crosslinkable polymers also provide here a ^r #eg to solve the problem (Gulbin, X., The leather 25 (1974) S, 121-126), the prerequisite is that a crosslinking is carried out under such conditions that the temperature sensitivity of the substrate Take into account.

Known for the finishing of leather are crosslinking mechanisms via isocyanate groups and functional groups which have a reactive hydrogen atom. You can already react at Haumtemperatur or slightly elevated temperature and represent so-called cold-curing or kaltvernetzende systems (DT-OS 1494845, DT-OS 1494853, DT-OS 2442761, DT-AS 1794263). By nature, such systems based on isocyanates for use in aqueous phase limits and attempts to avoid the Nacnteile of working in organic solvents to make about "capped isocyanates" the application in the aqueous phase possible. However, the use of higher temperatures or longer exposure time is required for the crosslinking.

Furthermore, the use of copolymers which contain N-substituted aminomethylenecarboxamide groups in the side chain of the polymer molecule (DT-AS 1278o64) is described for leather finishing. Polymers which contain both epoxy groups and aldehyde groups in side chains are also mentioned in the literature and are able to undergo crosslinking reactions under mild conditions (DT-AS Io76371).

The sensitivity of substituted acrylamides and unsaturated aldehydes, however, brings difficulties in the technical handling and in the execution of the polymerization process with it.

Ss are also known by the U3-PS 2 604 463 epoxy groups and carboxyl-containing copolymers с, which can also be prepared by emulsion polymerization. However, these copolymer dispersions do not lead to the required application properties in the finishing of leather.

Object of the invention

The object of the invention is to equip leather or leather-like materials in trouble-free working conditions and environmental pollution so that the utility properties or application properties, such. 3. a high resistance to mechanical stress in the. dry and moistened condition with sufficient hardness.

Presentation of the invention of the invention

- Problem of the invention

The invention is based-з the object, a process for trimming leather and leather-like üatjerialien by applying an aqueous dispersion of copolymers in a mixture mix; the usual additional ozts. Excipients a if the substrate to uncoil, the copolymers have reaküive groups in the side chains of the polymer molecules and the networking under mild conditions with sufficient pot life and the improvement of anvjecdungs üechnischen properties, preferably improving the Snickbeständigkeit with sufficient hardness achieved.

Features of the invention

The object is achieved in accordance with the invention in that the copolymers of the aqueous dispersion used before crosslinking have a characteristic C-value of 90 to 12C. The copolymers of the aqueous dispersion are composed of

A) 35 to 96 parts by weight of esters of ethylenically unsaturated monocarboxylic or dicarboxylic acids from an alcohol of up to 12 carbon atoms, preferably esters of acrylic acid a with alcohols of chain length C 1 to Cg,

B) 5 to 60 parts by weight of vinyl monomers, such as styrene, ε-metylstyrene, vinyl chloride, vinylidene chloride and vinyl esters of saturated carboxylic acids,

C) 1 to 15 parts by weight of ethylenically unsaturated, polymerizable mono- or dicarboxylic acids, such as acrylic acid, methacrylic acid, maleic acid or half esters of maleic acid and

D) 0.3 to 15 Ge-W. Ropes, preferably 1 to 5 wt .-%, epoxy groups, ethylenically unsaturated, polymerizable compounds, preferably glycidyl acrylate, glycidyl methacrylate or Alkylglycidäther. The copolymers contain in the side chains epoxy and carboxyl groups in the ratio 0.3 to 5 based on the equivalents.

The proportion of the monomers listed under A in the polymer; may vary widely in the region, while the proportion of the monomers listed in 3, especially the film hardness and hydrophobicity of the film, should not exceed 60%.

The crosslinking between the epoxy groups and the carboxy groups, which takes place when the temperature increases, can be catalyzed in a known manner by the addition of alkalis. The addition of aqueous ammonia or water-soluble amines is preferred. It is important that an optimum amount of added catalyst is ensured in terms of necessary pot life and sufficient crosslinking rate.

* The examples given below show that the dispersion obtained in a simple manner is that the dispersion obtained with a pH of 2.5 to 3.5 is in such a ratio of 7.5 to 10.5 »preferably 7, 5 to 8.5 »is raised. According to the invention, a certain, relatively high average molecular weight, which is most conveniently characterized by the determination of the Fikentscher K '' Vertes, is required for achieving the performance effect shown in the examples, in particular a good flexural bending behavior. The K values determined in 0.5% strength cyclohexanone solution at 25 ^° C., of course before the onset of crosslinking, are expected to be in the range

between 90 and 120 are.

As is known from the communication of 3AS5 ¹ (Leather 25, p.123 (1974), epoxy-group-like polymers can be obtained by the use of polymerizable glycidyl esters in the copolymerization, and min suitable Verneszern, such as polyamines or Säursanhydridan, can be Although low crosslinking temperatures are also achievable, but because of the sensitivity to compounds with active hydrogen, such copolymers can only be used in inert solvents, the use of the novel copolymers for the finishing of leather in aqueous dispersion is therefore surprising thus, unexpectedly in non-operating conditions and environmental burdens, the utility properties of the coated iJacerialien, in particular the resistance, against mechanical Beansprünnung in ъгоске-nen and moistened condition with sufficient hardness, vj8-senuliCQ against improve the previously known Verfanren. Зезсг-ders surprisingly тіаг that at the virtually infinite molecular weight leading Temeüzungsreakiiion the anverneün initially after the Polymerisaünn or largely unverneüst; resulting polymers such an extremely high K-ѵѴегтз or an excrem high high-ncnuulicnes molecular weight; so that, for the solution according to the invention, a mild, long-lasting, oil-rich environment can be crosslinked under mild conditions; - after completion of the vernier; -zungsreakt; ion - weitmaschigem network yields. The polymer dispersions are prepared in a known manner using ionogenic and / or nonionic emulsifiers and free-radical initiators, as described, for example, in Japanese Pat. No. 2 604 463. The size of the dispersed polymer particles should be determined be adjusted according to the requirements of the application by conventional methods, which are required for impregnation of leather very finely divided dispersions, optionally with the aid of water-soluble organic Lösungsmi "el and special surfactants.

The polymer dispersions may be mixed with customary leather adjuvants with pigment pastes customary in the finish color coating and applied to leathers of various provenances and pretreatment in accordance with the technologies introduced in the leather industry.

After drying and ironing, painting can be carried out with materials introduced in the leather industry.

embodiments

The invention will be explained in more detail in the examples cited below.

Example 1:

15o to 25o parts by weight of a forty-percent aqueous dispersion of a polymer of 73 parts by weight of butyl acrylate, 23 parts by weight of methyl methacrylate, 5 parts by weight of acrylic acid and 2 parts by weight of glycidyl methacrylate having a K value of Io5 adjusted with aqueous, concentrated ammonia to a pH value of 8 and with stirring with loo parts by weight of a conventional in the leather industry pigment paste and the usual auxiliaries z. 3. added plasticizers, matting agents and anti-adhesive agents and applied by means of a casting machine, plush apparatus and (or) spray gun on chrome-tanned leather in several layers. Between the individual jobs, ⁰ C is dried at 30 ° to 100 ° C. and ironed and / or embossed as required.

As a finish, a paint, e.g. casein, nitrocellulose or polyurethane based.

The usual leather test leads to the following results: Permanent bending behavior (measured with the Ballyflexometer): In dry condition after looooo buckling - perfect surface.

In the moistened state after 3 0000 kinks - perfect material surface.

Edging bow prooc bsi 12о G:

Impeccable material surface.

Adhesive strength in dry and flowering condition Grade: good

Rubbing fastness in dry, wet and well-moisturised condition. Grade: good

Example 2:

A dispersion of a polymer consisting of 78 parts by weight of butyl acrylate, 15 parts by weight of styrene, 5 parts by weight of acrylic acid and 2 parts by weight of glycidyl methacrylate mix; a value of Io2 used; and in the same manner as in Example 1.

The leather test led to equally good results as described in Example 1.

Example 3 '· (without component D of the invention)

The procedure corresponds to Example 1, that the copolymers used is composed of 7o parts by weight of butyl acrylate, 25 parts by weight of methyl methacrylate and 5 parts by weight of acrylic acid and has a λ / Iert of Io6.

Le test:

Daa Biegeverhalten (Ballyflexometer)

In the dry state after looooo buckling - formation of fine cracks.

After moistening after 5oooo buckling - formation of fine cracks.

Edge band test at 12o ° G:

partial damage of the material surface adhesion in dry and moistened state:

Note: moderate

Rubbing fastness in dry, wet and moist condition. Note: moderate.

Example 4:

The procedure of Example 1 is used, the copolymer consists as in Example 1 from 7o parts by weight of Acrylsäorebatylester, 25 parts by weight of methyl methacrylate and 5 parts by weight of acrylic acid. It has a K-lert of leather testing:

Bending Flexure Behavior (Ballyflexometer) In the dry state after looooo buckling - formation of coarse cracks, considerable disruption of the material surface.

In the moistened state after 25,000 bends - formation of coarse cracks, considerable disruption of the material surface.

Edge band test at 12o ° G:

considerable damage to the material surface.

Adhesive strength in dry and moistened condition Grade: moderate Eeibechtheit in dry, wet and moist condition Grade: moderate

- Io -

Claims (1)

- 10 - brfindungsansoruch Method for the Zuri ^ toei of leather u "i ¹ S ^ r ahn! Ιο ¹ ?. ⁰ η materials by applying a prior to the application to a pH of 7.5 to 10.5, preferably 7.5 to 3, 5, adjusted aqueous dispersion of Соpolymeren, which are composed of A) 35 to 96 parts by weight of esters of ethylenically unsubstituted mono- or dicarboxylic acids from an alcohol ai "up to 12 carbon atoms, preferably esters of acrylic acid with alcohols of the chain length Cj to Cg, 3) 5 to 60 parts by wt Monomers, εoyeeryrenes, C - - eth eth eth eth Vinyl, vinyl chloride, vinylidene chloride and vinyl esters of saturated carboxylic acids, C) 1 оіз 15 weight-line ä ^ byleniscn. unsaturated, polycrystallizable, mono- or dicarboxylic acids, acrylic acid, methylacrylic acid, lactic acid, and the like; Half of the ІІаіѳіпзаигз as well D) from 0.3 to 15 gram-д.-Іеііе, preferably 1 to 5 ue; -e.-2eile, epoxygruppenhaijige, ethylenically unsaturated, poir izzisierbare compounds, vorsugsgerje Jlycidylacryiat, GiycidylmeahacrylaT; or allcyglycidae, ucd in the lateral cerceri Зрсху and garboxy groups in the ratio of 0.3 to 3 enchal ^, in the Geaisoh with the usual additional benzyl. Auxiliary substances in the 3ubsurau, characterized in that the Copoiyneren used of the aqueous dispersion prior to crosslinking a S "7" c from 90 to 120 have. Documents considered: DD 84653 (C 14 C, 9/00)
DD 91120 (C 14 C, 9/00)
DE-AS 2043900 (C 14 C, 11/00)
US 2604463 (260-80.5)