Aqueous adhesive for leather and process for its preparation

Abstract

The application relates to the technical field of adhesives, and discloses a water-based adhesive for leather and a preparation method thereof, wherein the raw materials include, calculated in weight fractions, 55-80 parts of natural emulsion, 10-35 parts of high-styrene emulsion, 1-5 parts of nano-SiO2 emulsion, 0.5-3 parts of thickening agent and 0.5-3 parts of bactericide. The natural emulsion is modified by adding the high-styrene emulsion to improve the initial tackiness of the natural emulsion, and the water-based adhesive for leather does not contain organic solvents; the water-based adhesive for leather of the application can replace traditional oily adhesives containing organic solvents, can reduce the emission amount of organic solvents in the operation of using the adhesive to position the edges of the leather, and can reduce the pollution of the organic solvents to the operation environment and the influence of the organic solvents on the physical health of the operation personnel.

Description

TECHNICAL FIELD

[0001] The present application relates to the adhesive technical field, and particularly relates to a water-based adhesive for leather and a preparation method thereof. BACKGROUND

[0002] In order to make the leather products such as shoes and bags meet the shape structure requirements of design, in the production process, the edge part of the leather needs to be positioned by using an adhesive, and the adhesive used in the edge positioning of the leather in the prior art is an oily powder glue containing an organic solvent.

[0003] In the operation process of using the oily powder glue as the adhesive to position the edge of the leather, the organic solvent is continuously released, which causes chemical pollution to the operation environment and affects the health of the operation personnel. SUMMARY

[0004] In view of the above problems, a first object of the present application is to provide a water-based adhesive for leather, which does not contain an organic solvent, can replace the oily powder glue containing an organic solvent in the prior art, has better environmental protection performance, and can reduce the adverse effects on the health of the operation personnel.

[0005] A second object of the present application is to provide a method using the water-based adhesive for leather, and to limit the coating amount of the water-based adhesive for leather to ensure the bonding effect.

[0006] A third object of the present application is to provide a preparation method of the above water-based adhesive for leather, which has simple process and low preparation cost.

[0007] To achieve the above objects, the present application adopts the following technical solutions:

[0008] A water-based adhesive for leather, according to weight parts, raw materials include: 55-80 parts of natural latex, 10-35 parts of high styrene emulsion, 1-5 parts of nano-SiO2 emulsion, 0.5-3 parts of thickening agent and 0.5-3 parts of bactericide.

[0009] Specifically, the natural latex is low-ammonia natural latex with an ammonia content less than 0.25wt%.

[0010] Preferably, the solid content of the natural latex is greater than or equal to 61%.

[0011] Preferably, the content of nano-SiO2 particles in the nano-SiO2 emulsion is 20wt%.

[0012] Preferably, the mass concentration of styrene in the high styrene emulsion is 65wt%.

[0013] Preferably, the thickening agent is a thickening agent produced by Guangdong Nanhui New Material Co., Ltd., and the model number is CO-0015.

[0014] Preferably, the bactericide is a bactericide produced by Guangzhou Zhongwan New Material Co., Ltd., and the model number is WS-206.

[0015] Further, the present application proposes a method for using the above-mentioned water-based adhesive for leather, at least one layer of the water-based adhesive for leather is coated on the surface part to be bonded of the leather, and the coating amount of the water-based adhesive for leather on the surface part to be bonded is 300-350 g / m 2 .

[0016] Further, the present application also proposes a preparation method of a water-based adhesive for leather, which is used to prepare the above-mentioned water-based adhesive for leather, and comprises the following steps:

[0017] S1) according to the weight part, the natural latex, high styrene emulsion, nano-SiO2 emulsion, thickening agent and bactericide are weighed;

[0018] S2) start the reaction kettle, slowly add the formula amount of natural latex and high styrene emulsion into the reaction kettle under stirring, then add nano-SiO2 emulsion and bactericide in turn, stir uniformly, and prepare a mixed emulsion;

[0019] S3) add a thickening agent to the mixed emulsion to adjust the viscosity of the mixed emulsion, stir uniformly and detect the viscosity, and then filter, so as to prepare the water-based adhesive for leather.

[0020] Preferably, in step S3), the viscosity of the mixed emulsion added with the thickening agent is 4000-5000 cps / 25℃.

[0021] The above technical scheme of the present application has the following beneficial effects: the water-based adhesive for leather is modified by adding high styrene emulsion to natural latex to improve the initial adhesion of natural latex, and does not contain organic solvents, so that the water-based adhesive for leather of the present application can replace the traditional oily adhesive containing organic solvents, thereby reducing the emission amount of organic solvents in the operation of using the adhesive to position the edges of the leather product, and reducing the pollution of the operation environment and the influence on the health of the operation personnel.

[0022] Further, the present application proposes a method for using the water-based adhesive for leather, and clearly defines the coating amount of the water-based adhesive for leather, so as to ensure the bonding effect.

[0023] Further, the application also provides a preparation method of the water-based adhesive for leather. DETAILED DESCRIPTION

[0024] The technical solutions of the application are further described below through specific embodiments.

[0025] In the description of the present specification, the description referring to the terms "embodiment", "example", and the like means that the specific features, structures, materials, or characteristics described in connection with the embodiment or example are included in at least one embodiment or example of the present application. In the present specification, the illustrative description of the above terms does not necessarily refer to the same embodiment or example. Moreover, the specific features, structures, materials, or characteristics described can be combined in any one or more embodiments or examples in a suitable manner.

[0026] Although the embodiments of the present application have been shown and described, those of ordinary skill in the art can understand that various changes, modifications, replacements, and variations can be made to the embodiments without departing from the principles and spirit of the present application, and the scope of the present application is defined by the claims and their equivalents.

[0027] A water-based adhesive for leather, according to weight parts, raw materials include: 55-80 parts of natural latex, 10-35 parts of high styrene emulsion, 1-5 parts of nano-SiO2 emulsion, 0.5-3 parts of thickening agent and 0.5-3 parts of bactericide.

[0028] Natural latex is an environmentally friendly, naturally degradable, and renewable natural polymer material. Natural latex has high wet gel strength, and also has the advantages of good film elasticity, easy vulcanization, and small creep. Because the polarity of natural rubber is weak and the relative molecular weight is too large, the initial adhesion is poor, so it cannot directly replace the existing oil-based powder glue in the leather production process as an adhesive.

[0029] The water-based adhesive for leather of the present application is modified by adding high styrene emulsion to natural latex to improve the initial adhesion of natural latex, and does not contain organic solvents. By using the water-based adhesive for leather of the present application to replace the oil-based adhesive containing organic solvents in the prior art, the emission amount of organic solvents in the operation of using the adhesive to position the edges of leather can be reduced, thereby reducing the pollution of the operation environment and the impact on the health of the operation personnel.

[0030] The high-styrene emulsion added in the water-based adhesive for leather is a modifier, which can not only improve the adhesion of natural latex, but also improve the film hardness after film formation. If the amount of high-styrene emulsion is too small, the initial tackiness of natural latex in the formula is not improved enough, which leads to insufficient film hardness after film formation, and affects the adhesion and service life of the formed adhesive film. If the amount of high-styrene emulsion is too large, it will lead to too large viscosity of the water-based adhesive for leather, which is difficult to spread during coating, and is not conducive to construction operation. In addition, it will also shorten the time of maintaining the viscosity of the water-based adhesive for leather, and cause the undesirable phenomenon of edge springing due to premature curing of the adhesive layer.

[0031] The addition of an appropriate amount of thickening agent can adjust the viscosity of the adhesive and improve the convenience of construction operation.

[0032] The addition of a small amount of bactericide can kill the microorganisms and enzymes contained in the natural latex, thereby avoiding the chemical reaction of the microorganisms and enzymes contained in the natural latex, and further avoiding the undesirable phenomena of odor, discoloration or deterioration of the water-based adhesive for leather.

[0033] Specifically, the natural latex is a low-ammonia natural latex with an ammonia content of less than 0.25wt%.

[0034] The low-ammonia natural latex with an ammonia content of less than 0.25wt% not only has no obvious odor, but also can prolong the storage time of the water-based adhesive for leather.

[0035] Preferably, the solid content of the natural latex is greater than or equal to 61%.

[0036] The natural latex with a solid content of less than 61% contains more water, and the volatilization speed of water is slow. After brushing, the standing time is longer than that of traditional oil-based powder glue. When the user operates, the water may not be completely volatilized before the adhesive is attached, which can easily lead to insufficient adhesive strength of the adhesive layer after film formation, and further cause the phenomenon of leather edge springing caused by cracking of the adhesive layer.

[0037] Preferably, the content of nano-SiO2 particles in the nano-SiO2 emulsion is 20wt%.

[0038] The nano-SiO2 emulsion contains nano-SiO2 particles with a particle size of 1-100nm. These nano-SiO2 particles have a large specific surface area, and thus have a strong interfacial effect. They can not only significantly improve the dispersion uniformity of natural latex and high-styrene emulsion in the water-based adhesive for leather, but also make the water-based adhesive for leather have excellent light, force and / or heat absorption performance, thereby prolonging the service life of the adhesive layer after film formation.

[0039] Preferably, the mass concentration of styrene in the high styrene emulsion is 65 wt%.

[0040] The high styrene emulsion with a content of 65 wt% has a dispersity of 0.005-0.015 and a particle size of 150-200 nm, and has excellent mechanical stability and chemical stability.

[0041] Preferably, the thickening agent is a thickening agent with a model number of CO-0015 produced by Guangdong Nanhui New Material Co., Ltd.

[0042] Preferably, the bactericide is a bactericide with a model number of WS-206 produced by Guangzhou Zhongwan New Material Co., Ltd.

[0043] Further, the present application provides a method for using the water-based adhesive for leather described above, which comprises the following steps: 2 .

[0044] Further, the present application also provides a preparation method of a water-based adhesive for leather, which is used for preparing the water-based adhesive for leather described above, and comprises the following steps:

[0045] S1) according to the weight percentage, the natural latex, high styrene emulsion, nano-SiO2 emulsion, thickening agent and bactericide are weighed;

[0046] S2) start the reaction kettle, slowly add the formula amount of natural latex and high styrene emulsion into the reaction kettle under stirring, then add the nano-SiO2 emulsion and bactericide in turn, stir uniformly, and prepare a mixed emulsion;

[0047] S3) add the thickening agent to the mixed emulsion to adjust the viscosity of the mixed emulsion, stir uniformly and detect the viscosity, and then filter to prepare the water-based adhesive for leather.

[0048] The preparation method of the water-based adhesive for leather has simple operation process and low manufacturing cost.

[0049] Preferably, in step S3), the viscosity of the mixed emulsion with the thickening agent is 4000-5000 cps / 25℃.

[0050] The water-based adhesive for leather with a viscosity of 4000-5000 cps / 25℃ has appropriate flowability and is convenient for coating construction.

[0051] Examples 1-5 and Comparative Examples 1-3

[0052] 1. Refer to the raw materials and their proportions listed in Table 1 below, the water-based adhesive of Examples 1-5 and Comparative Examples 1-2 is prepared according to the following steps:

[0053] S1) according to the weight parts, the natural latex, high styrene emulsion, nano-SiO2 emulsion, thickening agent and fungicide are weighed;

[0054] S2) start the reaction kettle, slowly add the formula amount of natural latex and high styrene emulsion into the reaction kettle under stirring, then add nano-SiO2 emulsion and fungicide in turn, stir uniformly, and prepare a mixed emulsion;

[0055] S3) add thickening agent to the mixed emulsion to adjust the viscosity of the mixed emulsion, stir uniformly and detect the viscosity, then filter, and the water-based adhesive for leather is prepared;

[0056] In step S3), the viscosity of the mixed emulsion with thickening agent is 4000-5000 cps / 25℃.

[0057] The solid content of the natural latex is 61%; the content of nano-SiO2 particles in the nano-SiO2 emulsion is 20wt%;

[0058] The natural latex is low ammonia natural latex with ammonia content less than 0.25wt%;

[0059] The mass concentration of styrene in the high styrene emulsion is 65wt%;

[0060] The thickening agent is a thickening agent produced by Guangdong Nanhui New Material Co., Ltd., model CO-0015.

[0061] The fungicide is a fungicide produced by Guangzhou Zhongwan New Material Co., Ltd., model WS-206.

[0062] 2. The adhesive used in Comparative Example 3 is an oil-based powder adhesive of a certain brand purchased in the market;

[0063] 3. The water-based adhesive for leather of each example and comparative example is tested for performance according to the following test method:

[0064] 3.1 Peeling strength test: cotton canvas with a width of 25±0.2 mm and a length of 150±2 mm was used as the test substrate, 10 pieces of test substrate were taken as a test sample of an example or a comparative example each time, and the test sample was uniformly coated with the adhesive prepared in the example or the comparative example, the coating area had a width of 25±0.2 mm and a length of 120±2 mm, after standing for 5 minutes, a second layer of adhesive was applied on the surface of the first coating, and the total amount of adhesive used was controlled to be 1.125-1.3 g per piece, then after standing for 10 minutes, 10 pieces of test sample were paired into a group, and a pressure of 10 Kg was applied and maintained for 10 minutes, thereby five groups of test samples corresponding to the example or the comparative example were prepared, then the test samples were placed in an environment with a temperature of 25℃±2℃ and a relative humidity of 50%±5% for 24 hours, and the peeling strength of each group of test samples was tested and recorded according to GB / T 532-2008, the average of the five peeling strengths was taken as the peeling strength of the example or the comparative example, and the test results were recorded in Table 1.

[0065] 3.2 Edge pop-up test: two pieces of PU leather, two pieces of PVC leather and two pieces of microfiber leather with a width of 25±0.2 mm and a length of 150±2 mm were used as test materials, and the adhesive prepared in an example or a comparative example was uniformly coated thereon, the coating area was 10 mm*20 mm, the amount of adhesive used was 1.125-1.3 g per piece, and the test samples were paired after standing for 10 minutes, and a pressure of 10 Kg was applied and maintained for 10 minutes, then the test samples were placed in an environment with a temperature of 25℃±2℃ and a relative humidity of 50%±5% for 48 hours, and then placed in a 65℃ oven for 30 minutes, two test samples of each example or each comparative example were tested, whether the edge of each test sample popped up was observed, and the test results were recorded in Table 1.

[0066] Table 1: Raw materials, raw material ratio and test results of each example and comparative example

[0067]

[0068] As can be seen from the test results in Table 1, the water-based adhesive for leather prepared in Examples 1-5 of the present application can replace the existing oil-based powder adhesive, the peeling strength can reach not less than the bonding effect of the existing oil-based powder adhesive, and no adverse phenomenon of edge pop-up occurs.

[0069] The test results of Comparative Example 1 and Comparative Example 2 listed in Table 1 are analyzed: Comparative Example 1 differs from Example 5 in that the content of high-styrene emulsion added is 39 parts, which exceeds the upper limit of 10-35 parts of the added amount of high-styrene emulsion, and the excessive amount of high-styrene emulsion added in Comparative Example 1 shortens the viscosity maintenance time of the water-based adhesive for leather, resulting in the undesirable phenomenon of edge springing due to premature curing of the adhesive layer; Comparative Example 2 differs from Example 5 in that the content of high-styrene emulsion added is 8 parts, which is less than the lower limit of 10-35 parts of the added amount of high-styrene emulsion, resulting in an insufficient increase in the initial adhesion of the modified natural latex in the formula, and thus the undesirable phenomenon of edge springing also occurs.

[0070] In summary, the water-based adhesive for leather improves the initial adhesion of natural latex by adding high-styrene emulsion to modify the natural latex, and does not contain organic solvents. The use of the water-based adhesive for leather of the present application instead of traditional oil-based adhesives containing organic solvents can reduce the emission of organic solvents during the operation of edge positioning of leather using adhesives, thereby reducing the pollution of the operating environment and the impact on the health of the operating personnel.

[0071] Further, the present application proposes a method of using the water-based adhesive for leather and specifically limits the coating amount of the water-based adhesive for leather to ensure the bonding effect.

[0072] Further, the present application also proposes a preparation method of the water-based adhesive for leather, which has a simple operation process and low manufacturing cost.

[0073] The technical principles of the present application are described above in combination with specific embodiments. These descriptions are only for the purpose of explaining the principles of the present application and cannot be interpreted in any way as a limitation on the scope of protection of the present application. Based on the explanations herein, those skilled in the art can conceive other specific embodiments of the present application without creative labor, and these embodiments will fall within the scope of protection of the present application.

Claims

1. An aqueous adhesive for leather, characterized by, The raw materials include, by weight fraction, 55-80 parts of natural latex, 10-35 parts of high styrene emulsion, 1-5 parts of nano-SiO2 emulsion, 0.5-3 parts of thickening agent and 0.5-3 parts of bactericide; The mass concentration of styrene in the high styrene emulsion is 65 wt%, the dispersity of the high styrene emulsion is 0.005-0.015, and the particle size is 150-200 nm; The solid content of the natural latex is ≥61%; The content of nano-SiO2 particles in the nano-SiO2 emulsion is 20 wt%; The thickening agent is a thickening agent produced by Guangdong Nanhui New Material Co., Ltd., with a model number of CO-0015; The viscosity of the water-based adhesive for leather is 4000-5000 cps / 25℃.

2. The aqueous adhesive for leather according to claim 1, characterized by, The natural latex is low-ammonia natural latex with an ammonia content of less than 0.25 wt%.

3. The aqueous adhesive for leather according to claim 1, characterized by The bactericide is a bactericide produced by Guangzhou Zhongwan New Material Co., Ltd., with a model number of WS-206.

4. A method of using the water-based adhesive for leather according to any one of claims 1 to 3, characterized in that, The water-based adhesive for leather is applied to at least one surface portion to be bonded of the leather in an amount of 300 to 350 g / m 2 .

5. A process for the preparation of an aqueous adhesive for leather, characterized in that, A method for preparing the water-based adhesive for leather according to any one of claims 1-3, comprising the following steps: S1) weighing the natural latex, high styrene emulsion, nano-SiO2 emulsion, thickening agent and bactericide according to weight fraction; S2) starting a reaction kettle, slowly adding the formula amount of natural latex and high styrene emulsion into the reaction kettle under stirring, then sequentially adding the nano-SiO2 emulsion and bactericide, stirring uniformly, and preparing a mixed emulsion; S3) adding the thickening agent to the mixed emulsion to adjust the viscosity of the mixed emulsion, stirring uniformly and detecting the viscosity to be qualified, and then filtering, to prepare the water-based adhesive for leather.

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