RU2260607C1 - Sheet porous collagen-containing material and a method for manufacturing thereof - Google Patents

Abstract

FIELD: polymer materials.

SUBSTANCE: sheet porous collagen-containing material, suited to be used in footwear, furniture, and vehicle manufacture, comprises water-soluble plasticizer and particles of hydrophilic filler in the form of fibers with length-to-diameter ratio between 5 and 500. At least 50% of fibers are parallel to sheet sides with largest surface areas. This sheet is characterized by rupturing relative elongation when stretched in one direction in planes of the largest sides equal to 10-30%, modulus of compression elasticity for thickness equal to 50-300 kPa, and coefficient of thickness restoration after 70% compression for 5 h equal to 0.90-0.95 at 8-12% moisture. Also described is method of manufacturing such material including following operations: mixing hydrophilic fibers having length-to-diameter 5-500 with aqueous collagen solution and multifunctional cross-linking agent to form homogenous mass containing 1-20% fibers, 1-5% collagen, and 0.2-20% cross-linking agent; freezing liquid sheet and unfreezing it followed by pressing resulting porous sheet; softening with water-soluble plasticizer; second pressing; and drying.

EFFECT: enhanced damping ability of sheet and simplified manufacturing technology.

8 cl, 2 tbl, 10 ex

Description

The invention relates to the technology of polymers and relates to the production of porous sheet of cologan-containing material, which can be used in the manufacture of footwear, furniture and transport, mainly for the manufacture of elastic shock-absorbing pads.

A significant number of sheet porous collagen-containing materials and methods for their preparation are known.

So known sheet porous collagen-containing material (Patent RU No. 2070560 C1, class C 08 H 1/06, publ. 12/20/1996), including water-soluble plasticizer and particles of a hydrophilic filler, uniformly distributed in the mass of the sheet, which is characterized by an elongation at break 10 -15% and the amount of hydrophilic filler up to 25% in terms of dry matter.

A method of obtaining this sheet material includes preparing a homogeneous mass containing collagen, water, particles of a hydrophilic filler, a multifunctional crosslinking agent (glutaraldehyde), molding a homogeneous mass into a liquid sheet, freezing and thawing it, followed by pressing and drying the resulting porous sheet, plasticization which is provided by the introduction of a water-soluble plasticizer (glycerin) directly into a homogeneous mass. In this known method, as a hydrophilic filler, finely dispersed activated carbon is used as a targeted medical supplement.

The resulting porous collagen-containing sheet material is a very soft finely porous sponge with a small tensile strength (0.1-0.4 MPa), as a result of which it can be successfully used in medicine as a dressing or filter material, but is completely unsuitable for manufacturing shock absorbing elastic elements for shoes or for soft upholstery.

Also known is a method of producing a porous sheet of collagen-containing material (Patent RU No. 2001921 C1, class C 08 H 1/06, publ. 10/30/1993), which involves mixing particles of a hydrophilic filler (particles of crushed waste tanned leather) with an aqueous solution of collagen (with the product of dissolution of collagen in an aqueous solution of o-phosphoric acid) and the addition of a multifunctional crosslinking agent (glutaraldehyde) to obtain a homogeneous mass, molding a homogeneous mass into a liquid sheet, freezing and thawing a homogeneous mass with osleduyuschim squeezing and drying the resulting porous sheet.

Using this rather simple known method, a porous collagen-containing sheet material is obtained that includes particles of a hydrophilic filler uniformly distributed in the sheet mass, which is characterized by a relative elongation in tension of 20-28%.

This known material has a low tensile strength (0.495-0.575 MPa), is practically inelastic and brittle, as a result of which it is completely unsuitable for the manufacture of shock-absorbing gaskets.

Closest to the invention is a known method for producing sheet porous collagen-containing material (Patent RU No.2018540 C1, class C 14 C 13/00, 08/30/1994), which involves mixing particles of a hydrophilic filler with an aqueous solution of collagen and adding a multifunctional crosslinking agent to obtain a homogeneous mass containing collagen, filler and a multifunctional cross-linking agent, molding a homogeneous mass into a liquid sheet, freezing and thawing it, followed by squeezing the resulting porous sheet, plastic pecifications and a second spin.

In this known method, tanning leather waste particles 0.2-0.6 mm in size are used as a hydrophilic filler. As a result of such special operations carried out after squeezing the resulting porous sheet, such as hot pressing and holding in air for 12-24 hours, a surface hardened porous prefabricated sheet is obtained. This semi-finished product is subjected to further special leather processing, including the following sequentially performed finishing operations: washing with water and spinning; neutralizing emulsion and spin treatment; dyeing, fatliquoring (plasticization) and wringing; retanning and spinning; storing the material in air for 12-24 hours and cyclic extraction with moisturizing at 50 ° C; pulling and softening operations.

After performing all the numerous technological stages, a porous collagen-containing material is obtained, which includes a plasticizer and particles of a hydrophilic filler uniformly distributed in the sheet mass.

This material is similar to natural leather (it has a sufficiently high moisture and gas permeability, strength, elasticity and a certain elasticity), which is why it is quite suitable for the exterior decoration of the salons and seats of aircraft and cars, for the manufacture of upper parts of shoes. However, the low cushioning ability does not allow to produce elastic shoe pads from it, as well as the elastic elements of upholstered furniture, aircraft and automobile seats.

The objective of the invention is to create a high-tech durable hygienic material suitable for the manufacture of shock absorbing pads for shoes and furniture, by increasing the cushioning ability of sheet porous collagen-containing material while simplifying the technology of its production mainly from waste from other industries (leather, paper, textile, etc.).

Such a technical result as an increase in the cushioning ability of the material is achieved due to the fact that in a sheet of porous collagen-containing material comprising a plasticizer and particles of a hydrophilic filler uniformly distributed in the mass of the sheet, according to the invention, the plasticizer is water-soluble, the hydrophilic filler particles are hydrophilic fibers, in which the ratio of length to diameter is 5-500 and at least 50% of which are parallel to the largest in area of the sides of the sheet, which has a discontinuous the relative elongation in tension in one direction in the planes of the largest sides is 10-30%, the elastic modulus in compression in thickness is 50-300 KPa, and the coefficient of restoration of thickness after 70% compression for 5 hours is 0.90-0.95 at 8-12% leaf moisture.

In the invented material, the water-soluble plasticizer may be any of a number of known, for example, glycerin, 1,4-butanediol, ethylene glycol or polyethylene glycol. Hydrophilic fibers can be any natural, artificial, or synthetic fiber with a length to diameter ratio of 5-500 — a value associated with a characteristic combination of mechanical properties that causes a high cushioning ability of the material. Such parallel fibers, evenly distributed in the sheet mass, being firmly connected to each other by the elastic-elastic collagen walls of the cells, form a system of coupled spring-loaded collagen elements that determine the required cushioning quality of the porous material.

To improve the hygienic quality of the material, hydrophilic fibers of natural origin (paper and / or cotton and / or linen fibers and / or tanned leather fibers) with a diameter of 0.01-0.1 mm and a length of 0.5-5 mm are preferred, thanks to which it is possible to obtain the best special case of material execution, characterized by

- water holding capacity, wt.% 50-250 - relative vapor permeability,% 40-80 - tensile strength in one direction in the planes of the largest sides of the sheet, MPa 1-5 - content in terms of dry matter, wt.%: - collagen (collagen proteins) 5-60 - water soluble plasticizer 10-30 - hydrophilic fibers 20-85

Moreover, such a parameter as “water-holding capacity” is determined by the formula G = (M ₂ -M ₁ ): M ₁ : 100, where:

G, in wt.% - water-holding ability;

M ₁ , in g is the weight of the original air-dry sample of the material;

- M ₂ , in g is the weight of the same sample, measured after its next treatment: exposure to water at 20 ± 5 ° C for 1 hour; extraction from water with the subsequent extraction of mechanically held water under a load of 0.1 MPa and removal of water from all external surfaces of the sample with filter paper.

The same complex technical result as increasing the cushioning ability of a sheet of porous collagen-containing material while simplifying the technology for its preparation is achieved due to the fact that in the method of producing a sheet of porous collagen-containing material, comprising mixing particles of a hydrophilic filler with an aqueous solution of collagen and adding a multifunctional cross-linking agent to obtain homogeneous mass containing collagen, filler and polyfunctional crosslinking agent, ph molding a homogeneous mass into a liquid sheet, freezing and thawing it, followed by pressing the resulting porous sheet, plasticizing and second pressing, according to the invention, hydrophilic fibers are used as particles of a hydrophilic filler, in which the ratio of length to diameter is 5-500, in an amount of 1- 20 wt.% With 1-5 wt.% Collagen and 0.2-2 wt.% Polyfunctional cross-linking agent in a homogeneous mass, which is formed with the orientation of the fibers parallel to the largest on the sides of the liquid sheet, plasticization wasp estvlyayut water soluble plasticizer, and after the second pressing porous sheet is further dried.

To achieve the claimed technical result, it is important to use an aqueous solution of collagen, which will actively moisten the hydrophilic fibers in the process of mixing, which ensures the strength of the fixation of the fibers in the collagen mass of the finished material.

The claimed technical result is not affected by the type of polyfunctional crosslinking agent, which can be used glutaraldehyde, oxidized starch, hexamethylene diisocyanate and others.

However, the experimentally selected asymmetry of the fiber is essential: the ratio of its length to diameter should be in the range of 5-500. This geometry allows the fibers to easily disperse in a viscous aqueous collagen solution without messing up (i.e., without forming conglomerates), which contributes to the subsequent orientation of the fibers parallel to the largest in area of the sides of the liquid sheet.

Moreover, as already noted above, in order to achieve the best hygienic quality of the material obtained, it is preferable to use paper and / or cotton and / or linen fibers and / or tanned leather fibers with a diameter of 0.01-0.1 mm and a length of 0.5- 5 mm.

The experimentally selected boundaries of the allowable quantitative ranges of the main components of a homogeneous mass (collagen 1-5 wt.%, Hydrophilic fibers 1-20 wt.% And polyfunctional crosslinking agent 0.2-2.0 wt.%) Provide reproducible production of the material of the required quality.

The mandatory plasticization by any water-soluble plasticizer is caused, on the one hand, by the need to give the cells of the resulting porous material the desired elasticity, and on the other hand, by the need to ensure high hygienic quality of the sheet porous material.

As a series of experiments showed, plasticization is best done by exposure of the porous sheet in a 5-10% aqueous plasticizer solution for 30-90 minutes at a temperature of 20-60 ° C. The higher the temperature, the shorter the duration of plasticization, because the process of diffusion of the plasticizer into the mass of the porous sheet is accelerated. However, exceeding 60 ° C can lead to undesirable shrinkage of the porous sheet due to denaturation changes in the collagen macromolecule.

For the same reason, the final drying, necessary to remove excess moisture, is preferably carried out directly in air at 20-60 ° C until the equilibrium state is up to 8-12% humidity of the resulting sheet porous collagen-containing material.

Thus, the best case of the method is characterized by the use of paper and / or cotton and / or tanned leather fibers with a diameter of 0.01-0.1 mm and a length of 0.5-5 mm, using a water-soluble plasticizer, plasticization by exposure of the porous sheet to 5 -10% aqueous plasticizer solution for 30-90 minutes at a temperature of 20-60 ° C and drying directly in air at 20-60 ° C to an equilibrium state - up to 8-12% humidity of the resulting sheet porous collagen-containing material.

Studies have shown that the dependence of the rate of structure formation on temperature when freezing a liquid sheet of a homogeneous collagen-containing mass is extreme. The maximum of this speed is observed at minus 10 - minus 15 ° С. Therefore, for freezing a homogeneous mass, the temperature range of minus 5 - minus 20 ° C was selected as the most technologically advantageous from the point of view of the duration of the structuring process.

The invention is as follows.

The aqueous collagen solution necessary for the implementation of the proposed method can be prepared by a well-known method - by dissolving collagen in an aqueous acid solution - acetic, o-phosphoric and others (Golovteeva A.A., Kuditsi D.A., Sankin L.B. Laboratory practice in chemistry and technology of leather and fur. - M.: Light and food industry, 1986, P.310), including using substandard leather industry wastes as a feedstock (see the aforementioned Patent RU No. 1854040).

The necessary hydrophilic fibers can be obtained by conventional methods for the disposal of appropriate waste. So cotton or linen fibers can be made from scraps of fabric on rotary-knife type grinders. Tanning fibers of any kind of tanning are obtained by dry grinding of tanning waste on rotary knife grinders or in the presence of a certain amount of water using knife or abrasion type homogenizers, as well as on cavitation machines. By selecting the operating mode of the respective grinding equipment, one obtains fibers with a length to diameter ratio of 5-500, and the one that provides a fiber diameter of 0.01-0.1 mm with a length of 0.5-5.0 should be recognized as the best grinding mode mm

After calculating the required amounts of components in advance, the hydrophilic fibers are mixed with a previously prepared aqueous solution of collagen in any mixing device (cutter, planetary type mixer), which provides a mixture of viscous masses to a homogeneous state.

After adding a multifunctional crosslinking agent with continuous stirring of the mass until it is homogeneous with the required combination of components (1-20% hydrophilic fibers, 1-5% collagen, 0.2-2.0% polyfunctional agent, the rest is water, usually with a pH of 2 , 0-7.0), the formation of a homogeneous mass into a liquid sheet is carried out with the fibers oriented parallel to the largest sides of the sheet. To do this, a homogeneous mass is squeezed out through a rectangular channel (for example, 800 mm × 10 mm with a linear section length of 250 mm) with a mass flow rate providing orientation of the fibers in the flow plane onto a metal carrier (pallet) in the form of a 1000 mm long liquid sheet. An acceptable mass flow rate is determined on the basis of a series of preliminary experiments by analyzing the degree of fiber orientation achieved using an optical microscope with a 50X-100X magnification.

Next, carry out the usual process of cryostructuring a homogeneous mass. A tray with a liquid sheet of homogeneous mass is placed in a low-temperature refrigerator, where it is frozen to a cryostructure temperature (minus 5 ° С - minus 20 ° С), kept frozen for the time required for crystallization of the water contained in the mass, and then thawed exposure to air or blowing a stream of warm air with a temperature of 40-60 ° C. The defrosting process is considered complete when the reaction of the crosslinking agent with collagen is completed. The completion of this chemical reaction can be controlled by reaction with trinitrobenzenesulfonic acid. The process can be considered completed if at least 90% of the available amino groups have reacted.

The resulting cryogel porous sheet with dimensions, for example, 800 mm × 500 mm × 10 mm, is squeezed to remove moisture mechanically bound by its pores, passing through squeeze rollers. At a rolling pressure in the range of 0.5-2.0 MPa, a porous sheet with approximately 80% humidity is obtained.

Next, the porous sheet is placed for 30-90 minutes in a 5-10% aqueous plasticizer solution with a temperature of 20-60 ° C, the second time it is squeezed out and dried in air, for example, by blowing at a temperature of 20-60 ° C to an air-dry state - to a residual moisture content of 8-12%.

Specific modes of 9 examples of the method are shown in Table 1, and the corresponding parameters of the obtained samples of sheet porous collagen-containing material are shown in Table 2.

As can be seen from Table 2, in a technologically simple way that allows you to dispose of waste from leather, paper and textile industries, it is possible to obtain a highly hygienic elastic sheet material, which with significant compression is characterized by a fairly low residual deformation and at the same time a very slight expansion in the sheet plane, which leads to its shock-absorbing quality, similar to that possessed by Neopolen foam plastic (AA Berlin, F.A. Shutov. Chemistry and technology of gas-filled high polymers, Moscow, Izd. ments "Science", p.386). Therefore, the invented material can be successfully used for the manufacture of elastic elements of footwear (especially orthopedic, sports and children's), upholstered furniture, aircraft seats and automobiles, which are traditionally made of synthetic elastic polystyrene. Surprisingly high water-holding capacity is a particularly valuable property of shock-absorbing elastic shoe pads made from the invented porous collagen-containing sheet material, because it provides a comfortable condition for a person’s legs for a long time of continuous wearing.

Note to Table 1 "Examples of the method for producing sheet porous collagen-containing material":

* GDA - glutaraldehyde;

** OK - oxidized starch;

*** HMDIC - hexamethylenediisocyanate;

T ₁ , ° C - freezing temperature of a homogeneous mass;

K ₁ - the concentration of an aqueous solution of plasticizer;

T ₂ , ° С - plasticization temperature;

τ, min - the duration of exposure in an aqueous solution of plasticizer;

T ₃ , ° C - drying temperature;

φ,% - residual moisture content of the obtained material.

Note to Table 2 "Parameters of a sheet of porous collagen-containing material":

ε,% - tensile elongation in tension in one direction in the planes of the largest sides of the sheet;

K is the coefficient of restoration of the sheet thickness after 70% compression for 5 hours;

G, wt.% - water-holding ability;

P,% - relative vapor permeability;

σ, MPa - ultimate tensile strength in one direction in the planes of the largest in area of the sides of the sheet;

E, kPa - modulus of elasticity in compression over the thickness of the sheet;

And,% - the content of fibers parallel to the largest in area of the sides of the sheet.

Claims (8)

1. Sheet porous collagen-containing material, including plasticizer and particles of a hydrophilic filler, uniformly distributed in the mass of the sheet, characterized in that the plasticizer is water-soluble, the particles of hydrophilic filler are hydrophilic fibers in which the ratio of length to diameter is 5-500 and not less than 50% which are parallel to the largest in area of the sides of the sheet, in which the tensile elongation in tension in one direction in the planes of the largest sides is 10-30%, the modulus The compressive strength in thickness is 50–300 KPa, and the coefficient of thickness recovery after 70% compression for 5 hours is 0.90–0.95 at 8–12% sheet moisture. 2. The material according to claim 1, characterized in that the hydrophilic fibers in it are paper and / or cotton and / or linen fibers and / or tanned leather fibers with a diameter of 0.01-0.1 mm and a length of 0.5 -5 mm and it is additionally characterized Water retention ability, wt.% 50-250 Relative vapor permeability,% 40-80 Tensile Strength in One Direction in the planes of the largest sides of the sheet, MPa 1-5 The content in terms of dry matter, wt.%: Collagen (Collagen Protein) 5-60 Water soluble plasticizer 10-30 Hydrophilic fibers 20-85 3. A method of obtaining a sheet of porous collagen-containing material, comprising mixing particles of a hydrophilic filler with an aqueous solution of collagen and adding a multifunctional crosslinking agent to obtain a homogeneous mass containing collagen, filler and multifunctional crosslinking agent, molding a homogeneous mass into a liquid sheet, freezing and thawing it, followed by the extraction of the resulting porous sheet, plasticization and the second extraction, characterized in that as particles of a hydrophilic filler is used use hydrophilic fibers, in which the ratio of length to diameter is 5-500, in an amount of 1-20 wt.% with 1-5 wt.% collagen and 0.2-2 wt.% polyfunctional crosslinking agent in a homogeneous mass, which is formed with by orienting the fibers parallel to the largest in area of the sides of the liquid sheet, plasticization is carried out by a water-soluble plasticizer, and after the second extraction, the porous sheet is additionally dried. 4. The method according to claim 3, characterized in that as the hydrophilic fibers use paper, and / or cotton, and / or linen fibers, and / or tanned leather fibers with a diameter of 0.01-0.1 mm and a length of 0.5 -5 mm. 5. The method according to paragraph 3, characterized in that the plasticization of the porous sheet is carried out by exposure to 5-10% aqueous plasticizer solution for 30-90 minutes at a temperature of 20-60 ° C. 6. The method according to claim 3, characterized in that the drying of the porous sheet is carried out in air at a temperature of 20-60 ° C to 8-12% humidity. 7. The method according to claim 3, characterized in that as the hydrophilic fibers use paper, and / or cotton, and / or linen fibers, and / or tanned leather fibers with a diameter of 0.01-0.1 mm and a length of 0.5 -5 mm, plasticization of the porous sheet is carried out by exposure to a 5-10% aqueous plasticizer solution for 30-90 minutes at a temperature of 20-60 ° C, and drying is carried out in air at 20-60 ° C to 8-12% - Noah humidity. 8. The method according to any one of claims 3 to 7, characterized in that the freezing of a homogeneous mass is carried out at a temperature of minus 5 - minus 20 ° C.