CN107118656B - A kind of rubber anti-aging coating and its preparation method and application - Google Patents

Abstract

The present invention provides a kind of rubber ageing-proof coating and the preparation method and application thereof, and including the component with following weight, total weight is 1000 parts, 200~350 parts of resin, 0.2~3.5 part of auxiliary agent, 0~5 part of POSS, 641.5~799.8 parts of water；It can be used as rubber coating.Contain POSS (Polyhedral oligomeric silsesquioxanes) in rubber ageing-proof coating of the present invention, the intensity after coating film forming not only can be improved in the POSS, its caged stereochemical structure keeps self-molecules present size larger, become potential physical crosslinking point in the coating, facilitate the solidification crosslinking of coating, to improve coat inside structural stability, the sealing performance and thermal stability of coating are effectively increased.When the additive amount of POSS is 0.2%, the improvement of coating for rubber is most obvious, tensile strength 9.2MPa, elongation at break 620%.

Description

A kind of rubber anti-aging coating and its preparation method and application

technical field

The invention relates to a rubber anti-aging coating technology, in particular to a rubber anti-aging coating and a preparation method and application thereof, belonging to the field of coatings.

Background technique

Nitrile rubber is one of the seven major rubber types in the world today. It is widely used in military, automobile, aerospace, shoemaking and other industries. It has excellent oil resistance, low temperature resistance, high temperature resistance, wear resistance, and compression deformation resistance. Under the action of external environmental factors such as ozone, ultraviolet light and humidity, the surface structure of rubber products changes, showing aging phenomena such as loss of light, discoloration and hardening, chalking and cracking, which leads to the decline of rubber performance. Under normal circumstances, delaying the occurrence of rubber aging reaction is mainly achieved by adding various chemical substances, such as antioxidants, ultraviolet light absorbers, or coating the rubber surface with anti-aging coatings.

There are also some patents about applying anti-aging coating on rubber surface to achieve anti-aging purpose. For example, Chinese invention patent (application number: 201110164095.7, application date: 2011-06-17) proposes a double-rubber anti-corrosion coating and The preparation method comprises, by weight, 1 part of chlorinated rubber, 0.5-0.8 parts of chlorinated ethylene vinyl acetate copolymer, 3.1-3.7 parts of xylene, 0.1-0.15 parts of n-butanol, 0.1-0.2 parts of acrylic resin, 0.2-0.35 parts of Parts of rutile titanium dioxide, 0.05 to 0.1 parts of talc, 0.05 to 0.1 parts of mica powder, 0.01 to 0.02 parts of dispersant, 0.005 to 0.02 parts of titanate coupling agent, 0.005 to 0.02 parts of silicone defoamer, 0.005 to 0.02 part of leveling agent; made by mixing, high-speed dispersion and grinding. When used, a coating film is formed with the volatilization of the solvent. It has the advantages of resistance to erosion of various chemical media, good adhesion and flexibility, and good resistance to water vapor permeability. Its application fields are mainly in steel structures such as platforms, ships, bridges, buildings, etc., but the anti-aging effect of elastomer rubber is not ideal. Chinese invention patent (application number: 200510036963.8, application date: 2005-09-02) proposes a rubber anti-aging coating, which is mainly composed of polyurethane rubber. It is prepared by the process of processing rubber. The rubber anti-aging coating is characterized by spraying or brushing on the surface of various rubber products and tires. It can effectively prevent the aging effect caused by ozone, oxygen, sunlight, etc. Extend the storage and service life of rubber products and tires. It can also prevent the corrosion of rubber products and tires by gasoline, diesel oil, engine oil, lubricating oil, etc. The main disadvantage: the main body is oil-soluble paint, and the organic solvent pollutes the environment during use. Chinese invention patent (application number: 201410840983.X, application date: 2014-12-29) proposes an oil-resistant and anti-aging protective coating for rubber vibration isolators and a preparation method thereof. Aiming at the shortcomings of poor anti-aging and oil resistance of the rubber base material for vibration isolators, a protective coating is prepared to improve the anti-aging and oil-resistant properties of the isolator rubber, thereby prolonging the service life of the rubber vibration isolator and ensuring power The overall safety of the equipment and the normal operation of each component. The oil-resistant and anti-aging protective coating for rubber vibration isolators is mainly composed of component A and component B. Oil-resistant and anti-aging protective coatings for rubber vibration isolators. Component A is composed of polyaspartate, carbon black, carbodiimide, light stabilizer, 8-hydroxyquinolinone, dispersant, leveling agent, organic bentonite, Matting agent and mixed solvent composition. The B component is composed of hydroxyl-terminated polyester resin, aliphatic isocyanate, trimethylolpropane, amino-terminated polysiloxane, dibutyltin dilaurate and mixed solvent. This method has disadvantages such as complicated coating formulation and coating operation, and high cost.

There are also patents that improve anti-aging properties by adding substances to rubber. For example, Chinese invention patent (application number: 201410831379.0, application date: 2014-12-26) proposes a polyhedral oligomeric silsesquioxane modified liquid Silicone rubber and preparation method thereof. In the method, polyhedral oligomeric silsesquioxane (POSS) is designed to synthesize a series of vinyl-ethoxy-T8-silsesquioxane (Vi-Eo-POSS), and a In order to be added to the silicone rubber system as a functional additive of the silicone rubber system, the reliability and life of the silicone rubber products are improved. However, the preparation method is cumbersome, and the used reagent is an organic solvent, which is easy to cause environmental pollution.

In view of this, the present invention proposes a rubber anti-aging coating and its preparation method and application to solve the above problems.

SUMMARY OF THE INVENTION

The object of the present invention is to overcome the deficiencies of existing products, and to provide a kind of rubber anti-aging coating and its preparation method and application. It can improve the strength of the coating after film formation. Its cage-like three-dimensional structure makes its own molecular size larger and becomes a potential physical cross-linking point in the coating, which is helpful for the curing and cross-linking of the coating, thereby improving the stability of the internal structure of the coating. It can effectively increase the sealing performance and thermal stability of the coating.

In order to achieve the above purpose, the technical scheme adopted in the present invention is: a rubber anti-aging coating, comprising the following components, the total weight is 1000 parts, 200-350 parts of resin, 0.2-3.5 parts of auxiliary, POSS 0 ~ 5 parts, water 641.5 ~ 799.8 parts.

Further, the resin includes one or more of acrylic resin, acrylic polyurethane, water-based polyurethane, and water-based epoxy resin.

Further, the auxiliary agents include wetting agents, dispersing agents, rheological auxiliary agents, defoaming agents, film-forming auxiliary agents, cross-linking curing agents, antioxidants, and light stabilizers.

Further, the POSS is isobutylpropylamino-POSS.

A preparation method of a rubber anti-aging coating, comprising the following preparation process:

Step (1): place resin, auxiliary agent and water in a reaction vessel in a certain proportion, mix and dissolve until there is no obvious block or sheet material in the system, and finally obtain a uniform emulsion;

Step (2): isobutylpropylamino-POSS is dissolved in water, for subsequent use;

Step (3): adding the isobutylpropylamino-POSS solution dissolved in the step (2) into the emulsion prepared in the step (1), and ultrasonically mixing the POSS without agglomeration in the system to obtain a coating uniformly dispersed with POSS.

Further, the described isobutylpropylamino-POSS needs to be dissolved in step (2) to obtain the butylpropylamino-POSS aqueous solution, and then the butylpropylamino-POSS aqueous solution is added dropwise to the prepared by step (1). in the emulsion to avoid agglomeration of isobutylpropylamino-POSS.

An application of a rubber anti-aging coating for rubber. The specific operation steps are as follows:

The coating is evenly coated on the rubber surface with a film applicator to form a uniform anti-aging film with a thickness of 1 to 2.5 mm, and the coated sample is placed in an oven for thermal-oxidative aging simulation experiments. The curing temperature is 100 ° C -150℃, curing time is 12～96h.

Further, the temperature during coating is 80°C to 100°C to avoid curling due to the failure of the coating layer to cure in time due to interfacial tension.

The beneficial effects of the present invention are:

1. POSS (polyhedral oligomeric silsesquioxane) has a unique intramolecular organic-inorganic hybrid structure, and the inorganic silicon-oxygen cage structure makes it have significant stability, and can be used as a physical cross-linking point in the curing of coatings, It is helpful for the curing and crosslinking of the coating; its eight corner substituents can improve its compatibility with other substrates, make it evenly dispersed in the coating, and improve the strength of the coating film; at the same time, it can also be used without affecting the On the basis of the processability of rubber products, reduce the viscosity of the polymer;

2 The internal structural stability of the coating is improved by adding POSS to the coating, which effectively improves a number of performance indicators of the nitrile rubber in the thermo-oxidative aging test. The improvement effect is the most obvious, the tensile strength is 9.2MPa, and the elongation at break is 620%; it can effectively strengthen the surface of nitrile rubber products to resist the invasion of external aging factors, which opens up a new way for the research of rubber anti-aging coatings;

3. The present invention mainly adopts the method of physical addition, only needs to effectively control the temperature in the production process, the overall operation is simple and convenient, the implementation is strong, the cost is reasonable, and the improvement effect on the rubber properties is obvious, which can well meet the batch size. production requirements.

Description of drawings

Fig. 1 is the dispersion diagram of the POSS described in the embodiment two and four of the present invention in the coating;

Fig. 2 is the relation diagram of Shore hardness and poss content of the rubber anti-aging coatings described in Embodiments 1 to 6 of the present invention;

3 is a graph showing the relationship between the elongation at break and the aging time of the rubber anti-aging coatings according to Embodiments 1 to 6 of the present invention;

FIG. 4 is a graph showing the relationship between the tensile strength and the aging time of the rubber anti-aging coatings according to Examples 1 to 6 of the present invention.

Detailed ways

In order to better understand the present invention, the content of the present invention is further explained below in conjunction with the accompanying drawings and embodiments, but the content of the present invention is not limited to the following embodiments.

Example 1

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system materials, and finally obtain a uniform emulsion, which is referred to as liquid A; 0.2 part of isobutylpropylamino-POSS is dissolved in 197.8 parts of deionized water, which is referred to as liquid B. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Embodiment 2

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system Finally, a uniform emulsion was obtained, which was recorded as liquid A; 0.4 part of isobutylpropylamino-POSS was dissolved in 197.6 parts of deionized water, which was recorded as liquid B. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Embodiment 3

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system materials, and finally a uniform emulsion was obtained, which was recorded as liquid A; 0.6 part of isobutylpropylamino-POSS was dissolved in 197.4 parts of deionized water, which was recorded as liquid B. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Embodiment 4

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system material, and finally obtain a uniform emulsion, which is referred to as A liquid; 0.8 part of isobutylpropylamino-POSS is dissolved in 197.2 parts of deionized water, which is referred to as B liquid. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Embodiment 5

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system materials, and finally obtain a uniform emulsion, denoted as A solution; dissolve 1 part of isobutylpropylamino-POSS into 197 parts of deionized water, denoted as B solution. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Embodiment 6

The total weight is 1000 parts, 200 parts of epoxy resin, 1 part of diethyl phthalate and 1 part of bentonite are added into a reaction vessel containing 598 parts of deionized water, and dissolved until there is no obvious block or flake in the system materials, and finally obtain a uniform emulsion, denoted as A liquid; 200 parts of deionized water, denoted as B liquid. Add B dropwise to solution A, and ultrasonicate for 10 minutes while adding dropwise; then at 80°C, use a 2mm film applicator to evenly coat the coating on the surface of the nitrile rubber, and finally transfer the rubber to a constant temperature drum of 100°C In an air drying oven, cure and keep warm for 24h.

Performance Testing

The POSS-containing rubber anti-aging coatings prepared in Examples 2 and 4 are tested for dispersibility. The results are shown in Figure 1. As can be seen from Figure 1, POSS is uniformly dispersed in the coating, that is, the compatibility of POSS with the coating. Sex is good.

The Shore hardness test was carried out on the rubber anti-aging coatings prepared in Examples 1 to 6. The results are shown in Figure 2. It can be seen from Figure 2 that under the condition of high temperature thermal oxygen at 100 ° C, with the prolongation of aging time, in In the process of thermo-oxidative aging of nitrile rubber, the products after chain scission are intertwined, which destroys the elastic structure of the rubber, the rubber becomes hard and brittle, and the Shore A hardness increases. Aging is fastest when no POSS is added. With the increase of amino POSS content, the Shore hardness of nitrile rubber decreases gradually and reaches the minimum value at 0.2%. The main reason is that the added amino POSS is dispersed in the coating in molecular form, which effectively increases the sealing performance and thermal stability of the coating. As the content of POSS continued to increase, the Shore hardness of nitrile rubber began to increase, because POSS could no longer exist in molecular form and began to agglomerate, which seriously affected the morphology of the coating film.

The rubber anti-aging coatings prepared in Examples 1 to 6 were tested for elongation at break and aging time. The results are shown in Figure 3. As the aging time increases, the elongation at break of nitrile rubber also follows. Increase. In the process of thermo-oxidative aging, the products after chain scission are mainly intertwined, which destroys the elastic structure of the rubber and makes the rubber brittle. When the functional POSS is added to the coating film, the heat resistance of the coating film is increased, which effectively blocks oxygen from entering the inside of the rubber. However, at about 50h, the coating film also began to fail, and the rubber aging rate was significantly accelerated. Secondly, it can also be seen that different POSS contents will also affect the aging process of rubber. When the POSS content is 0.1% and 0.2%, the aging resistance of rubber is obviously better than that of no addition and addition of 0.3%, 0.4%, 0.5% system. The main reason for the latter three is that the content of POSS is too high and cannot be completely dissolved in the coating solvent, which directly affects the thermo-oxidative aging performance of nitrile rubber.

The tensile strength and thermal aging time of the rubber anti-aging coatings prepared in Examples 1 to 6 were tested. The results are shown in Figure 4. It can be seen from Figure 4 that with the extension of the thermal aging time, the nitrile rubber The tensile strength gradually decreased. Compared with the nitrile rubber coated with no POSS coating, the tensile strength of the nitrile rubber coated with the POSS coating was improved. It shows that the addition of POSS in the coating can indeed improve the anti-aging performance of the rubber. This is because the POSS group, as an excellent additive, can improve the strength of the coating film layer. Secondly, the cage-like three-dimensional structure of the POSS group has a relatively small molecular size. Large, it is a potential cross-linking point, which helps the curing and cross-linking of the coating. With the increase of POSS content, the tensile strength of nitrile rubber increased first and then decreased, mainly because more cross-linking points were provided for the coating with the increase of POSS content. The maximum value was reached when the content of POSS was 0.2%. When the content of POSS was further increased, the system reached saturation, and the excess POSS was precipitated from the solvent in the form of agglomeration, forming "white spots". In the process of coating the film, these "white spots" seriously affect the morphology of the film, and there is a phenomenon that the film cannot be formed locally, thus affecting the protection of the nitrile rubber by the anti-aging film.

The rubber anti-aging coatings prepared in Examples 1 to 6 were subjected to thermo-oxidative aging experiments according to GB/T3512-1989, and the thermo-oxidative aging was performed for 48 hours. And according to GB/T528-1992, the mechanical properties of nitrile rubber samples were tested.

Table 1 Effects of different POSS contents on the elongation at break of rubber

As can be seen from Table 1, compared with the tensile strength and elongation at break of the rubber coated with no POSS coating, the samples prepared in Examples 1, 2, 3, 4 and 5 coated with POSS coating The tensile strength and elongation at break of the rubber increased significantly, indicating that the addition of POSS further improved the anti-aging properties of the rubber. The main reason is that isobutylpropylamino-POSS, as a nano-scale inorganic additive, can effectively increase the stability of the internal structure of the coating, and can also form effective physical cross-linking points in the coating, so an appropriate amount in the coating can be used. The addition of isobutylpropylamino-POSS, and then applying this coating to the rubber can improve the stability of the rubber.

The above-mentioned embodiments illustrate the present invention in detail. Of course, the above description does not limit the present invention, and the present invention is not limited to the above-mentioned examples. Changes, modifications, additions or reductions, and substitutions made by those skilled in the art within the scope of the present invention also belong to the protection scope of the present invention.

Claims (3)

1. a kind of rubber ageing-proof coating, which is characterized in that including the component with following weight, total weight is 1000 parts, tree 200~350 parts of rouge, 0.2~3.5 part of auxiliary agent, 0~5 part of POSS, 641.5~799.8 parts of water, POSS is not equal to zero；

The resin be include one or more of acrylic resin, aqueous polyurethane, aqueous epoxy resins；

The auxiliary agent includes wetting agent, dispersing agent, auxiliary rheological agents, defoaming agent, coalescing agent, crosslinking and curing agent, antioxidant or light Stabilizer；

The POSS is the third amino of isobutyl group-POSS.

2. a kind of preparation method of rubber ageing-proof coating described in claim 1, which is characterized in that prepared including following Journey:

Step (1): resin, auxiliary agent and water are placed in reaction vessel by a certain percentage, are mixed and are dissolved until without bright in system Aobvious blocky or sheet material, finally obtains uniform lotion；

Step (2): the third amino of isobutyl group-POSS is dissolved in water phase, spare；

Step (3): isobutyl group the third amino-POSS solution that step (2) is dissolved being added in the lotion of step (1) preparation, Ultrasonic mixing does not have the POSS to reunite into system, obtains the evenly dispersed coating for having POSS；

Third amino-the POSS of isobutyl group, which needs first to dissolve in step (2), obtains isobutyl group the third amino-POSS aqueous solution, Then isobutyl group the third amino-POSS aqueous solution is added drop-wise in lotion prepared by step (1) again, to avoid the third ammonia of isobutyl group There is agglomeration in base-POSS.

3. a kind of application of rubber ageing-proof coating described in claim 1, which is characterized in that can be used for rubber, concrete operations Steps are as follows:

Coating is uniformly coated on rubber surface with coating device, forms the uniform anti-aging film with a thickness of 1~2.5mm, it will Coated sample is placed in progress thermo-oxidative ageing simulated experiment in baking oven, and solidification temperature is 100 DEG C -150 DEG C, curing time 12 ~96h；Temperature when film is 80 DEG C~100 DEG C, is caused to avoid because coat is made to fail solidification in time for interfacial tension It rolls up.