CN114250019A

CN114250019A - Leather surface modifier, composition for forming same and application

Info

Publication number: CN114250019A
Application number: CN202111663279.8A
Authority: CN
Inventors: 吴阳贵
Original assignee: Shengrui Changzhou Special Materials Co ltd
Current assignee: TFL (Changzhou) Co.,Ltd.
Priority date: 2021-12-30
Filing date: 2021-12-30
Publication date: 2022-03-29
Anticipated expiration: 2041-12-30
Also published as: CN114250019B

Abstract

The invention provides a leather surface modifier, a composition for forming the same and application thereof. The composition for forming the leather surface improver comprises: aqueous polymer resin, hollow material, filler and water; the refractive index of the hollow material is 1.48-1.52; the average particle diameters of the hollow material and the filler are respectively and independently selected from 1-30 mu m; the weight ratio of the hollow material to the filler is (3-10) to (10-20). Compared with the traditional leather surface modifying agent, the leather surface modifying agent provided by the application can improve the light transmittance of a coating film formed on the surface of leather. The average particle diameters of the hollow material and the filler are smaller, and the hollow material and the filler are matched with the waterborne polymer resin for use, so that tiny flaws on the surface of leather can be modified; meanwhile, compared with other dosage ranges, the weight ratio of the hollow material to the filler is limited within the preferable range, so that the light transmittance of the coating film can be improved, and the coating film can be prevented from shielding the surface texture of the original leather.

Description

Leather surface modifier, composition for forming same and application

Technical Field

The invention relates to the technical field of leather processing and manufacturing, in particular to a leather surface modifier, a composition for forming the leather surface modifier and application of the leather surface modifier.

Background

Leather is divided into finished leather and full grain leather, and the leather factory adopts a roller coater to repair and mend the damage aiming at the obviously slightly larger damage on the surface of the finished leather at present, so that time and labor are saved. The vast majority of the surface of the full grain or buffed leather has some tiny flaws, such as pinholes, sand holes and other tiny flaws, and the distribution of these tiny flaws is not uniform. At present, the leather making factory fills the damaged parts with the decorative materials by hand to achieve the effect of filling and repairing the damaged parts, and the method has the following defects: a large amount of labor is consumed; the filled part and the adjacent unfilled part are easy to generate part difference in the properties of hardness, water absorption and the like, and have obvious influence on the subsequent process. In addition, the special roller coater is used for repairing and decorating the leather, so that a large amount of labor can be saved, but the method also has the obvious defects: the roller coating amount is large, a large amount of chemical materials are wasted, the original natural leather is thick and heavy, and the effect of filling and repairing tiny wound is obviously poor.

On the basis, researches and developments on a leather surface modifier with high transmittance are significant for improving tiny flaws such as pinholes and sand holes of the leather and preventing the leather from becoming thicker and heavier.

Disclosure of Invention

The invention mainly aims to provide a leather surface modifier, a composition for forming the leather surface modifier and application of the leather surface modifier, and aims to solve the problems that a coating formed by the leather surface modifier in the prior art is poor in light transmittance and filling effect, and thick and heavy.

In order to accomplish the above object, the present invention provides, in one aspect, a composition for forming a leather surface improver, the composition for forming a leather surface improver comprising: aqueous polymer resin, hollow material, filler and water; the refractive index of the hollow material is 1.48-1.52; the average particle diameters of the hollow material and the filler are respectively and independently selected from 1-30 mu m; the weight ratio of the hollow material to the filler is (3-10) to (10-20).

Further, the composition for forming the leather surface modifier comprises the following components in parts by weight: 35-50 parts of water-based polymer resin, 3-10 parts of hollow material, 10-20 parts of filler and 10-30 parts of water.

Further, the hollow material is selected from acrylic acidEster compounds and/or acrylonitrile compounds, the average particle diameter of the hollow material is 10-30 mu m, and the density is 0.033-0.039 g/cm³。

Further, the ratio of the average particle diameter of the hollow material to the average particle diameter of the filler is (10-30) to (2.5-11); preferably, the filler is selected from one or more of the group consisting of kaolin, ground calcium carbonate and silica; preferably, the D50 value of the silicon dioxide is 2-7 μm.

Further, the aqueous polymer resin is selected from polyacrylic resin and/or epoxy resin; preferably, the weight average molecular weight of the polyacrylic resin is 20000-80000, and the epoxy equivalent of the epoxy resin is 900-1200 eq/mol.

Further, the composition for forming a leather surface improver further comprises: penetrants, oil waxes, emulsifiers, and stabilizers; preferably, the composition for forming the leather surface improver further comprises, in parts by weight: 2-5 parts of penetrating agent, 10-20 parts of oil wax, 2-5 parts of emulsifier and 1-3 parts of stabilizer; preferably, the oil wax is mixed with water to form an oil wax emulsion, and the D50 value of the oil wax emulsion is 1-30 μm.

Further, the penetrating agent is selected from one or more of the group consisting of dioctyl sodium sulfosuccinate, isomeric tridecanol polyoxyethylene ether and guerbet alcohol polyoxyethylene ether; the oil wax is selected from one or more of animal oil and fat obtained by natural extraction, polyamide wax and natural vegetable wax; the emulsifier is one or more selected from fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether and oleyl alcohol polyoxyethylene ether; the stabilizer is selected from polyacrylic resin polymer, associated polyurethane polymer, cellulose compound and lithium magnesium silicate compound.

Further, the composition for forming the leather surface modifier comprises the following components in parts by weight: 35-40 parts of water-based polymer resin, 3-10 parts of hollow material, 12-15 parts of filler, 10-30 parts of water, 2-3 parts of penetrating agent, 15-20 parts of oil wax, 3-4 parts of emulsifier and 1.5-2.5 parts of stabilizer.

In order to achieve the above objects, another aspect of the present invention also provides a leather surface improver prepared from the above composition for forming a leather surface improver provided herein.

In order to achieve the above object, the present invention also provides in another aspect a use of the above leather surface modifier provided herein in the processing and manufacturing field of leather.

By applying the technical scheme of the invention, the leather surface modifier can be obtained by mixing the water-based polymer resin, the filler, the water and the hollow material with specific density and refractive index. Compared with the traditional leather surface modifying agent, the leather surface modifying agent provided by the application can improve the light transmittance of a coating film formed on the surface of leather. The average particle diameters of the hollow material and the filler are smaller (1-30 mu m), and the hollow material and the filler can be used together with the waterborne polymer resin to modify tiny defects such as pinholes, sand holes, pores and the like on the surface of the leather; meanwhile, compared with other dosage ranges, the weight ratio of the hollow material to the filler is limited in the preferable range, so that the light transmittance of the coating film can be improved while tiny flaws on the surface of the leather are modified, the original leather surface texture is prevented from being shielded by the coating film, and the leather grade is improved. In addition, compared with the composition only comprising the aqueous polymer resin, the filler and the water, the hollow material is introduced into the composition for forming the leather surface modifying agent, so that the weight of a coating film formed on the surface of leather can be reduced, and the composition is lighter and thinner; and the grain surface of the leather after the modification and the mending is uniform and consistent, and the hand feeling is smooth and fine.

Drawings

The accompanying drawings, which are incorporated in and constitute a part of this application, illustrate embodiments of the invention and, together with the description, serve to explain the invention and not to limit the invention. In the drawings:

FIG. 1 shows a photograph of a real object of an original leather surface without finishing;

FIG. 2 shows a photograph of a real object of a portion of the surface of an original leather without finishing, magnified 20 times;

FIG. 3 shows a photograph of a real object of the leather surface after the touch-up was decorated as obtained in example 1;

FIG. 4 is a photograph of the leather surface after the touch-up modification made in example 1, partially enlarged by 20 times;

FIG. 5 shows a photograph of a real object of the leather surface after the touch-up was decorated, which was obtained in comparative example 1;

fig. 6 shows a photograph of a real object of the leather surface after the touch-up of the touch-up prepared in comparative example 1 at a local magnification of 20 times.

Detailed Description

It should be noted that the embodiments and features of the embodiments in the present application may be combined with each other without conflict. The present invention will be described in detail with reference to examples.

As described in the background art, the conventional leather surface modifier has the problems of poor light transmittance, poor filling effect and thick and heavy coating film of the coating film formed by the conventional leather surface modifier. In order to solve the above technical problems, the present application provides a composition for forming a leather surface improver, the composition for forming a leather surface improver comprising: aqueous polymer resin, hollow material, filler and water; the refractive index of the hollow material is 1.48-1.52; the average particle diameters of the hollow material and the filler respectively and independently include but are not limited to 1-30 mu m; the weight ratio of the hollow material to the filler is (3-10) to (10-20).

The leather surface modifier can be obtained by mixing the water-based polymer resin, the filler and water with the hollow material with specific density and refractive index. Compared with the traditional leather surface modifying agent, the leather surface modifying agent provided by the application can improve the light transmittance of a coating film formed on the surface of leather. The average particle diameters of the hollow material and the filler are smaller (1-30 mu m), and the hollow material and the filler can be used together with the waterborne polymer resin to modify tiny defects such as pinholes, sand holes, pores and the like on the surface of the leather; meanwhile, compared with other dosage ranges, the weight ratio of the hollow material to the filler is limited in the preferable range, so that the light transmittance of the coating film can be improved while tiny flaws on the surface of the leather are modified, the original leather surface texture is prevented from being shielded by the coating film, and the leather grade is improved. In addition, compared with the composition only comprising the aqueous polymer resin, the filler and the water, the hollow material is introduced into the composition for forming the leather surface modifying agent, so that the weight of a coating film formed on the surface of leather can be reduced, and the composition is lighter and thinner; and the grain surface of the leather after the modification and the mending is uniform and consistent, and the hand feeling is smooth and fine.

In a preferred embodiment, the composition for forming the leather surface-modifying agent comprises, in parts by weight: 35-50 parts of water-based polymer resin, 3-10 parts of hollow material, 10-20 parts of filler and 10-30 parts of water. The amount of the aqueous polymer resin, the hollow material, the filler and the water includes, but is not limited to, the above range, and the limitation of the amount to the above range is advantageous for improving the light transmittance of the coating film formed on the leather surface by the leather surface improving agent, and is further advantageous for improving the leather grade; meanwhile, the method is favorable for improving the effect of modifying and repairing tiny flaws on the surface of the leather. In addition, the weight of the coating film is reduced, and the decorated leather is lighter and thinner.

In a preferred embodiment, the hollow core material includes, but is not limited to, an acrylate compound and/or an acrylonitrile compound. Compared with other types, the hollow material is beneficial to matching the refractive index of the hollow material with the refractive index of other components in the coating film, reducing the haze of the coating film, further improving the light transmittance of the coating film, further avoiding the coating film from shielding the surface texture of the original leather, and further being beneficial to improving the leather grade.

In a preferred embodiment, the hollow material has an average particle size of 10 to 30 μm and a density of 0.033 to 0.039g/cm³. The average particle size and density of the hollow material include, but are not limited to, the above ranges, and the limitation of the average particle size and density to the above ranges is beneficial to better control the scattering of light in the coating film, further reduce the haze of the coating film, further improve the light transmittance of the coating film, and further avoid the shielding of the coating film on the surface texture of the original leather; meanwhile, the weight of a coating formed on the surface of the leather is further reduced, so that the leather is lighter and thinner.

In a preferred embodiment, the ratio of the average particle diameter of the hollow material to the average particle diameter of the filler is (10-30): 2.5-11. The ratio of the average particle size of the hollow material to the average particle size of the filler includes, but is not limited to, the above range, and limiting the ratio in the above range is beneficial to exerting the synergistic effect of the filler and the hollow material, so that the filler and the hollow material can better control the scattering of light in the coating film, the haze of the coating film can be further reduced, the light transmittance of the coating film can be further improved, and the leather grade can be further improved; meanwhile, the filling agent can be matched with the size of the tiny flaws on the surface of the leather better, and the filling effect can be better exerted.

In order to further exert the filling effect on the minute flaws on the leather surface while further improving the light transmittance of the coating film, it is preferable that the filler includes one or more of the group consisting of, but not limited to, kaolin, ground calcium carbonate, and silica.

In order to further exhibit the effect of filling minute flaws in the leather surface and further improve the light transmittance of the coating film, the D50 value of silica is preferably 2 to 7 μm.

In a preferred embodiment, the waterborne polymer resin includes, but is not limited to, polyacrylic resins and/or epoxy resins. Compared with other kinds of waterborne polymer resin, the waterborne polymer resin is beneficial to improving the permeation of the resin to leather, further beneficial to improving the filling effect, and simultaneously further improving the light transmittance of the coating film, further avoiding the shielding of the coating film on the surface texture of the original leather; meanwhile, the wetting property and the dispersibility of the waterborne polymer resin to hollow materials and fillers are facilitated.

The degree of crosslinking or molecular weight of the waterborne polymer resin may affect its own refractive index. In order to further improve the wettability and dispersibility of the hollow material and the filler and further improve the light transmittance of the coating film and the permeability of the leather, the polyacrylic resin preferably has a weight average molecular weight of 20000 to 80000 and the epoxy resin preferably has an epoxy equivalent weight of 900 to 1200 eq/mol.

The addition of the penetrant can reduce the interfacial tension of the leather modifier and is beneficial to the penetration of the waterborne polymer resin into leather. The addition of the oil wax can play the oil wax effect, wherein the oil wax effect refers to that oil and wax with certain characteristics are applied to the surface of the leather, the absorption and refraction difference of the surface of the leather on light shows the effect of different color depths under the action of external force (stretching, jacking, bending and folding), and the color of the grain surface is naturally recovered after the external force is removed; meanwhile, the oil wax can also improve the hand feeling of the leather, cover the grain surface from being damaged and improve the roughness of the grain surface. The addition of the emulsifier is beneficial to reducing the interfacial tension of each component in the leather modifier and improving the mixing uniformity of each raw material component in the composition. The addition of the stabilizer is beneficial to inhibiting the phenomena of precipitation and the like of the leather modifier, improving the compatibility and mixing uniformity of each raw material component in the composition, improving the stability of the leather modifier and prolonging the service life of the leather modifier. In a preferred embodiment, the composition for forming a leather surface improver further comprises: penetrant, oil wax, emulsifier and stabilizer.

In order to further improve the comprehensive properties such as permeability, stability and the like of the leather modifier, further improve the light transmittance of a coating film and further improve the hand feeling of leather, the composition for forming the leather surface modifier preferably further comprises the following components in parts by weight: 2-5 parts of penetrating agent, 10-20 parts of oil wax, 2-5 parts of emulsifier and 1-3 parts of stabilizer.

In order to further improve the dispersibility of the oil wax in the leather modifier and further reduce the haze of the coating film, the oil wax is preferably mixed with water to form an oil wax emulsion, and the D50 value of the oil wax emulsion is preferably 1-30 μm.

In a preferred embodiment, the osmotic agent includes, but is not limited to, one or more of the group consisting of dioctyl sodium sulfosuccinate, isomeric tridecanol polyoxyethylene ethers, and primary alcohol polyoxyethylene ethers (such as basf, Lutensol XL); the oil wax includes, but is not limited to, one or more of the group consisting of naturally extracted animal fats and oils, polyamide wax, and natural vegetable wax; emulsifiers include, but are not limited TO, one or more of the group consisting of fatty alcohol polyoxyethylene ethers (such as peregal), isomeric alcohol polyoxyethylene ethers (such as basf, Lutensol TO), and oleyl alcohol polyoxyethylene ethers; stabilizers include, but are not limited to, polyacrylic polymers, associative polyurethane polymers, cellulosic compounds, and lithium magnesium silicate compounds. Compared with other varieties, the penetrating agent, the oil wax, the emulsifying agent and the stabilizing agent are adopted, so that the comprehensive performances of the leather modifier such as permeability, stability and the like can be further improved, the light transmittance of a coating film can be further improved, and the hand feeling of leather can be further improved.

In a preferred embodiment, the composition for forming the leather surface-modifying agent comprises, in parts by weight: 35-40 parts of water-based polymer resin, 3-10 parts of hollow material, 12-15 parts of filler, 10-30 parts of water, 2-3 parts of penetrating agent, 15-20 parts of oil wax, 3-4 parts of emulsifier and 1.5-2.5 parts of stabilizer. The proportion of the raw materials in the composition for forming the leather surface modifying agent includes, but is not limited to, the above range, and the limitation of the proportion to the raw materials in the composition is beneficial to improving the light transmittance of a coating formed on the surface of the leather, better playing the filling and modifying effects on tiny flaws on the surface of the leather, further reducing the weight of the coating and enabling the modified leather to be lighter and thinner; meanwhile, the comprehensive performances of permeability, stability and the like of the leather modifier are further improved, the light transmittance of a coating is further improved, and the hand feeling of leather is further improved.

In a second aspect, the present application provides a leather surface improver prepared from the above-described composition for forming a leather surface improver provided by the present application.

The application provides a leather surface modifying agent has the high advantage of light transmissivity at the coating film that the leather surface formed, simultaneously, can fill and decorate the tiny flaw on leather surface, avoids coating film to original leather surface texture's sheltering from, improves the leather grade. The leather surface modifier forms a coating film on the leather surface with light weight, so that the modified leather is lighter and thinner. In addition, the grain surface of the leather after the modification and the mending is uniform and consistent, and the hand feeling is smooth and fine.

The third aspect of the application also provides a preparation method of the leather surface modifier, and the preparation method of the leather surface modifier comprises the following steps:

(1) preparing a filler dispersion liquid: adding water into a reaction container, heating the water to 60-80 ℃, adding a stabilizer, cooling to below 40 ℃, adding a filler into a mixed solution of the water and the stabilizer, dispersing at a high speed of 800-1200 rpm by using a first homogenizer for 30-40 min, filtering and filling for later use; the reaction vessel includes, but is not limited to, a reaction kettle.

(2) Preparing oil wax emulsion: adding water, oil wax and an emulsifier into a reaction kettle, heating to 95-100 ℃, dispersing at a high speed of 2800-3000 rpm by adopting a second homogenizer for 40-60 min, and cooling to below 40 ℃ for later use.

(3) Preparing a leather surface modifier: and (2) introducing the aqueous polymer resin emulsion into a reaction container through vacuum suction or a manhole, adding the hollow material while stirring at a stirring speed of 7-25 rpm, stirring for 30-40 min, then sequentially pumping the filler dispersion liquid, the oil wax emulsion, the penetrating agent, the emulsifier and the stabilizer, stirring for 60min, adjusting the viscosity of the product to 1500-2500 mPa & s, and filtering to obtain the leather surface modifier.

The content of the effective substances of the leather surface modifier prepared by the preparation method is 25-35 wt%, the pH value is 8-10, the viscosity is 1500-2500 mPa.s, and the product stability result is as follows: the appearance of the product is not changed after 3 months at the temperature of 45 ℃.

It should be noted that the content of the active substance means the weight of all other components in the leather improver excluding water as a percentage of the total weight of the leather improver.

The fourth aspect of the present application also provides a method for dressing and repairing leather, which comprises:

the leather surface modifier provided by the application is reversely coated on the leather surface by a No. 14S roller of a Gemata STAPLUS-S roller coater, the speed of the upper roller is 70rpm, the transmission speed of a conveyor belt is 7m/min, the pressure is 0.3bar, the gap is 0.2mm, the coating amount is 2-3 g/sft, and after drying at 80-100 ℃, the modified leather is obtained by grinding with No. 600 abrasive paper. The reverse roll coating means that the conveying direction of a conveyor belt in a roll coater is opposite to the rotating direction of an upper roll in the roll coating process.

The fifth aspect of the application also provides an application of the leather surface modifier provided by the application in the field of processing and manufacturing of leather. The leather surface modifier provided by the application is particularly suitable for modifying tiny flaws such as pinholes, sand holes and pores on the surface of leather, can improve the light transmittance of a coating film, further avoids the shielding of the coating film on the surface texture of original leather, and improves the leather grade. In addition, the weight of a coating film formed on the surface of the leather can be reduced, so that the leather is lighter and thinner; and the grain surface of the leather after the modification and the mending is uniform and consistent, and the hand feeling is smooth and fine.

The present application is described in further detail below with reference to specific examples, which should not be construed as limiting the scope of the invention as claimed.

Example 1

The specific types and amounts of the components of the leather surface improver of example 1 are shown in Table 1. The parts by weight in table 1 refer to parts by weight of the solute in each component, not parts by weight of the dispersion (for example, the aqueous polymer resin emulsion of the components in table 1 refers to a dispersion of a polyacrylic resin, in which the polyacrylic resin is the solute, and the parts by weight of the solute is 35 parts). Wherein the weight average molecular weight of the polyacrylic resin is 30000, the refractive index of the hollow material is 1.4910, and the density is 0.033g/cm³The average particle size is 20 μm; the average particle diameter of the filler was 6 μm (the ratio between the average particle diameter of the hollow material and the average particle diameter of the filler was 20: 6); the particle size of the oil wax emulsion was 4 μm.

A preparation method of a leather surface modifier comprises the following steps:

(1) preparing a filler dispersion liquid: adding water into a reaction kettle, heating the water to 70 ℃, adding a stabilizer, cooling to 40 ℃, adding a filler into a mixed solution of the water and the stabilizer, dispersing for 30min at the rotating speed of 1000rpm by using a first homogenizer, filtering and filling for later use.

(2) Preparing oil wax emulsion: adding deionized water into the reaction kettle, adding the oil wax emulsion and the emulsifier, heating to 97 ℃, dispersing at high speed for 60min by adopting a second homogenizer, and cooling to 40 ℃ for later use. Wherein the D50 value of the oil wax emulsion is 5 +/-0.1 mu m.

(3) Preparing a leather surface modifier: and (2) pumping the aqueous polyacrylic resin emulsion into a reaction kettle in vacuum, adding the hollow material while stirring at the stirring speed of 10rpm, stirring for 30min, then sequentially pumping the filler dispersion liquid, the oil wax emulsion, the penetrating agent, the emulsifying agent and the stabilizing agent, stirring for 60min, adjusting the viscosity of the product to 1500-2500 mPa & s, and filtering to obtain the leather surface modifying agent.

TABLE 1

The leather surface modifying agent prepared by the method has the effective content of 29.3 percent, the pH value of 8.71 and the viscosity of 2100 mPas; and (3) product stability test results: the appearance of the product is unchanged after being placed for 3 months at the temperature of 45 ℃, and the product is still white.

A Gemata STAPLUS-S roller coater No. 14S is adopted to reversely roll and coat the leather surface modifying agent on the leather surface, the speed of an upper roller is 70rpm, the transmission speed of a transmission belt is 6m/min, the pressure is 0.8bar, the gap is 0.5mm, the roll coating amount is 4g/sft, and after drying at 90 ℃, the leather containing the modified coating is obtained by grinding with No. 600 sand paper. The photographs of the original leather surface without coating are shown in fig. 1 and 2, and the leather surface has fine defects such as pinholes, sand holes, and pores, and the original texture of the surface is clear. The photo of the leather surface after the modification and the enlarged partial view are respectively shown in fig. 3 and fig. 4, and it can be seen from comparing fig. 1 and fig. 3 and comparing fig. 2 and fig. 4, that the leather surface after the modification prepared in the embodiment 1 is relatively transparent and does not cover the texture of the original leather surface; meanwhile, the grain surface of the leather after the modification and the mending is uniform and consistent.

Example 2

The difference from example 1 is that: the amount of each component used in the leather surface improver was different from that of example 1 and is described in detail in Table 2. Note that the parts by weight in table 2 refer to parts by weight of the solute in each component, not parts by weight of the dispersion.

The kinds of the components in the leather surface improving agent were the same as in example 1, and the method for preparing the leather surface improving agent and the method for finishing and repairing the leather were the same as in example 1.

TABLE 2

Components	Parts by weight
		Aqueous polymer resin	40
Hollow material	5
		Filler	15
Oil wax	15
		Penetrant	4
Stabilizer	2
		Emulsifier	3
Water (W)	16

The leather surface modifier has effective content of 31.9%, pH of 8.65, and viscosity of 1960 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 3

The difference from example 1 is that: the amount of each component used in the leather surface improver was different from that of example 1 and is described in detail in Table 3. Note that the parts by weight in table 3 refer to parts by weight of the solute in each component, not parts by weight of the dispersion.

TABLE 3

Components	Parts by weight
		Aqueous polymer resin	44
Hollow material	8
		Filler	10
Oil wax	20
		Penetrant	5
Stabilizer	1
		Emulsifier	2
Water (W)	10

The leather surface modifier has an effective content of 33.8%, a pH of 8.53, and a viscosity of 1930 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Examples 4 to 6

The difference from example 1 is that: the amount of each component used in the leather surface improver was different from that of example 1 and is described in detail in Table 4. Note that the parts by weight in table 4 refer to parts by weight of the solute in each component, not parts by weight of the dispersion.

TABLE 4

Components	Example 4	Example 5	Example 6
				Aqueous polymer resin	50	35	30
Hollow material	10	3	2
				Filler	10	20	9
Oil wax	3	10	10
				Penetrant	3	3	3
Stabilizer	2	3	3
				Emulsifier	5	2	5
Water (W)	17	24	38

The leather surface improver obtained in example 4 had an active ingredient content of 31.8%, a pH of 8.86 and a viscosity of 1850 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

The leather surface improver prepared in example 5 had an active ingredient content of 28.3%, a pH of 8.78 and a viscosity of 2060 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

The leather surface improver prepared in example 6 had an active ingredient content of 26.1%, a pH of 8.76 and a viscosity of 2190mPa · s; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 7

The difference from example 1 is that: the weight ratio of the hollow material to the filler in the leather surface modifying agent is 3: 10.

The leather surface modifier has an effective content of 26.1%, a pH of 8.76, and a viscosity of 2190mPa & s; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 8

The difference from example 1 is that: the weight ratio of the hollow material to the filler in the leather surface modifying agent is 10: 20.

The leather surface modifier has an effective content of 30.6%, a pH of 8.80, and a viscosity of 2280 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 9

The difference from example 1 is that: the hollow material had an average particle diameter of 30 μm and a density of 0.033g/cm³。

The content of effective components in the leather surface modifier is 29.2%, the pH value is 8.70, and the viscosity is 2050 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 10

The difference from example 1 is that: the hollow material has an average particle diameter of 10 μm and a density of 0.039g/cm³。

The leather surface modifier prepared above has effective content of 29.3%, pH of 8.69, and viscosity of 2110 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 11

The difference from example 1 is that: the hollow material has an average particle diameter of 40 μm and a density of 0.021g/cm³。

The content of effective components in the leather surface modifier is 29.10%, the pH value is 8.70, and the viscosity is 1810mPa & s; and (3) product stability test results: standing at 45 deg.C for 3 months for layering.

Example 12

The difference from example 1 is that: the ratio of the average particle size of the hollow material to the average particle size of the filler was 30: 2.5.

The leather surface modifier has effective content of 29.5%, pH of 8.69, and viscosity of 1950 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 13

The difference from example 1 is that: the ratio of the average particle size of the hollow material to the average particle size of the filler was 10: 11.

The leather surface modifying agent prepared by the method has the effective content of 28.9 percent, the pH value of 8.72 and the viscosity of 2200 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 14

The difference from example 1 is that: the ratio of the average particle size of the hollow material to the average particle size of the filler was 40: 30.

The content of effective components in the leather surface modifier is 28.6%, the pH value is 8.50, and the viscosity is 1550mPa & s; and (3) product stability test results: standing at 45 deg.C for 3 months for layering.

Example 15

The difference from example 1 is that: the D50 value of the oil-wax emulsion was 1 μm.

The content of the effective substances in the leather surface modifying agent is 28.7 percent, the pH value is 8.10, and the viscosity is 2220 mPa.s; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 16

The difference from example 1 is that: the D50 value of the oil-wax emulsion was 30 μm.

The leather surface modifier prepared above has effective content of 29.10%, pH of 8.80, and viscosity of 2090 mPas; and (3) product stability test results: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Example 17

The difference from example 1 is that: the D50 value of the oil-wax emulsion was 40 μm.

The content of effective components in the leather surface modifier is 28.9%, the pH value is 8.75, and the viscosity is 1580mPa & s; and (3) product stability test results: standing at 45 deg.C for 3 months for layering.

Comparative example 1

The difference from example 1 is that: no hollow material was added.

The leather surface modifying agent prepared by the method has the effective content of 28.9 percent, the pH value of 8.71 and the viscosity of 2100mPa & s; and (3) product stability test results: the appearance of the product turns yellow after being placed at 45 ℃ for 3 months.

The photographs of the modified leather surface obtained in comparative example 1 are shown in FIGS. 5 and 6. As can be seen from comparison of fig. 3 and 5 and comparison of fig. 4 and 6, respectively, the leather in example 1 is more transparent and the original texture of the leather can be seen through the coating film in the modified leather prepared in comparative example 1, compared with the modified leather prepared in example 1, while the leather in comparative example 1 has a thicker surface, a higher haze and a poorer light transmittance, and the texture of the original leather surface cannot be seen.

Comparative example 2

The difference from example 1 is that: the refractive index of the hollow material was 1.65.

The preparation method of the leather surface modifier and the method for modifying and repairing the leather were the same as in example 1.

The obtained leather surface modifier has effective component content of 29.3%, pH of 8.70, and viscosity of 2160 mPas; product stability: the appearance of the product is not changed after the product is placed for 3 months at the temperature of 45 ℃.

Comparative example 3

The difference from example 1 is that: the weight ratio of the hollow material to the filler is 1: 30.

The obtained leather surface modifier has effective content of 35%, pH of 8.90, and viscosity of 2210mPa · s; product stability: the product appeared yellow in appearance and layered upon standing at 45 ℃ for 3 months.

From the above description, it can be seen that the above-described embodiments of the present invention achieve the following technical effects:

comparing example 1 with comparative example 1 and comparative example 2, it can be seen that the refractive index of the hollow material includes but is not limited to the preferred range of the present application, and that limiting the refractive index of the hollow material to the preferred range of the present application can improve the light transmittance of the coating film formed on the leather surface by the leather surface improving agent, compared to the conventional leather surface improving agent.

Comparing examples 1, 4 to 6 and comparative example 1, it can be seen that the amounts of the aqueous polymer resin, the hollow material, the filler and the water include, but are not limited to, the preferred ranges of the present application, and that limiting the amounts to the preferred ranges of the present application is advantageous for improving the light transmittance of the coating film formed on the leather surface by the leather surface improving agent, and thus for improving the leather grade; meanwhile, the effect of modifying and repairing tiny flaws on the surface of the leather is improved. In addition, the weight of the coating film is reduced, and the decorated leather is lighter and thinner.

Comparing examples 1, 7, 8 and comparative example 3, it can be seen that the leather surface improver prepared in comparative example 3 is much less stable; compared with other dosage ranges, the weight ratio of the hollow material to the filler is limited in the preferable range of the application, so that the light transmittance of the coating film can be improved while tiny flaws on the surface of the leather are modified, the covering of the coating film on the surface textures of the original leather is avoided, and the leather grade is improved.

Comparing examples 1, 9 to 11, it can be seen that the average particle size and density of the hollow material, including but not limited to the preferred range of the present application, are limited to the preferred range of the present application, which is beneficial to better control the scattering of light in the coating film, further reduce the haze of the coating film, further increase the light transmittance of the coating film, and further avoid the coating film from shielding the surface texture of the original leather; meanwhile, the weight of a coating formed on the surface of the leather is further reduced, so that the leather is lighter and thinner.

Comparing examples 1, 12 to 14, it is clear that the leather surface improving agent obtained in example 14 is much less stable; the ratio of the average particle size of the hollow material to the average particle size of the filler includes but is not limited to the preferred range of the application, and the limitation of the ratio to the preferred range of the application is favorable for playing the synergistic effect of the filler and the hollow material, so that the filler and the hollow material can better control the scattering of light in the coating film, the haze of the coating film is further reduced, the light transmittance of the coating film is further improved, and the leather grade is further improved; meanwhile, the filling agent can be matched with the size of the tiny flaws on the surface of the leather better, and the filling effect can be better exerted.

Comparing examples 1 and 15 to 17, it is understood that the leather surface improving agent obtained in example 17 is much less stable; and the particle size of the oil wax emulsion is limited in the preferable range of the application, so that the dispersibility of the oil wax emulsion in the leather modifier is further improved, and the haze of a coating film is further reduced.

It is noted that the terms first, second and the like in the description and in the claims of the present application are used for distinguishing between similar elements and not necessarily for describing a particular sequential or chronological order. It is to be understood that the terms so used are interchangeable under appropriate circumstances such that the embodiments of the application described herein are, for example, capable of operation in sequences other than those described or illustrated herein.

The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention, and various modifications and changes may be made by those skilled in the art. Any modification, equivalent replacement, or improvement made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. A composition for forming a leather surface modifying agent, the composition for forming a leather surface modifying agent comprising: aqueous polymer resin, hollow material, filler and water; the refractive index of the hollow material is 1.48-1.52; the average particle diameters of the hollow material and the filler are respectively and independently selected from 1-30 mu m; the weight ratio of the hollow material to the filler is (3-10) to (10-20).

2. The composition for forming a leather surface improver according to claim 1, characterized by comprising, in parts by weight: 35-50 parts of the waterborne polymer resin, 3-10 parts of the hollow material, 10-20 parts of the filler and 10-30 parts of water.

3. A composition for forming a leather surface improver according to claim 1 or 2, characterized in that the hollow material is selected from an acrylate compound and/or an acrylonitrile compound, has an average particle diameter of 10 to 30 μm and a density of 0.033 to 0.039g/cm³。

4. A composition for forming a leather surface improver according to claim 3, wherein the ratio between the average particle diameter of the hollow material and the average particle diameter of the filler is (10-30) to (2.5-11);

preferably, the filler is selected from one or more of the group consisting of kaolin, ground calcium carbonate and silica;

preferably, the D50 value of the silicon dioxide is 2-7 mu m.

5. The composition for forming a leather surface improver according to claim 4, characterized in that the aqueous polymer resin is selected from a polyacrylic resin and/or an epoxy resin;

preferably, the weight average molecular weight of the polyacrylic resin is 20000-80000, and the epoxy equivalent of the epoxy resin is 900-1200 eq/mol.

6. The composition for forming a leather surface improver according to claim 5, characterized by further comprising: penetrants, oil waxes, emulsifiers, and stabilizers;

preferably, the composition for forming a leather surface improver further comprises, in parts by weight: 2-5 parts of the penetrating agent, 10-20 parts of the oil wax, 2-5 parts of the emulsifier and 1-3 parts of the stabilizer;

preferably, the oil wax is mixed with the water to form an oil wax emulsion, and the D50 value of the oil wax emulsion is 1-30 μm.

7. The composition for forming a leather surface improver according to claim 6, wherein the penetrating agent is one or more selected from the group consisting of dioctyl sodium sulfosuccinate, isotridecanol polyoxyethylene ether, and guerbet alcohol polyoxyethylene ether;

the oil wax is selected from one or more of animal oil and fat obtained by natural extraction, polyamide wax and natural plant wax;

the emulsifier is selected from one or more of fatty alcohol polyoxyethylene ether, isomeric alcohol polyoxyethylene ether and oleyl alcohol polyoxyethylene ether;

the stabilizer is selected from polyacrylic resin polymers, associated polyurethane polymers, cellulose compounds and lithium magnesium silicate compounds.

8. The composition for forming a leather surface improver according to claim 6 or 7, characterized by comprising, in parts by weight: 35-40 parts of the water-based polymer resin, 3-10 parts of the hollow material, 12-15 parts of the filler, 10-30 parts of the water, 2-3 parts of the penetrating agent, 15-20 parts of the oil wax, 3-4 parts of the emulsifier and 1.5-2.5 parts of the stabilizer.

9. A leather surface improver characterized by being produced from the composition for forming a leather surface improver according to any one of claims 1 to 8.

10. Use of a leather surface modifier according to claim 9 in the field of leather processing and manufacture.