A green tire external spray liquid and preparation method thereof

Abstract

The invention provides a green tire external spray liquid and a preparation method thereof, wherein the green tire external spray liquid comprises, by mass, 8-15 parts of natural latex, 5-8 parts of carboxyl or sulfonic acid group modified synthetic latex, 2-4 parts of surfactant, 0.5-1.5 parts of filler, and 75-88 parts of deionized water. The green tire external spray liquid of the invention has a simple overall formula, is easy to make, has a low production cost, can effectively reduce tire vulcanization defects, and makes the tire have an excellent appearance. The carboxyl or sulfonic acid group modified synthetic latex and natural latex are compounded in a certain proportion to play a synergistic role, forming a layer of elastic film that is strongly bonded to rubber on the surface of the green tire, so that the tire can be easily and completely separated from the mold.

Description

Technical Field

[0001] The invention relates to the field of vulcanization release agents, and more specifically to a green tire external spray liquid and a preparation method thereof. Background Art

[0002] In the production process of tires, a vulcanization process is required, which generally adopts a model pressurization method. The characteristics of this vulcanization are that the outer surface of the rubber embryo contacts the metal mold, and the inner surface contacts the bladder. During the vulcanization process, the inflated bladder exerts pressure on the embryo and the metal mold to help the outer surface pattern and inner surface of the tire to be molded. In order to prevent adhesion between the green tire embryo and the metal mold, a release agent is required. Some release agents on the market now must be reapplied to the mold surface before manufacturing each tire. With the repeated use of the release agent, the release agent will accumulate on the mold surface to form scale, which will cause the mold surface feature structure to not be clearly printed on the surface of the tire, and the lack of glue, blistering, etc. will damage the integrity of the tire surface. The use of the release agent also requires the vulcanization worker to stand on the high-temperature vulcanization machine for spraying. The high temperature is easy to cause the unsafe working environment of the workers, and the release agent vaporized at high temperature also affects the health of the workers. In view of the problems and defects of the prior art, the research and development of the green tire external spray is of great significance. Summary of the invention

[0003] The present invention provides a green tire external spray liquid and a preparation method, and the specific technical scheme is as follows:

[0004] A green tire external spray liquid, comprising, by weight: 8-15 parts of natural latex, 5-8 parts of carboxyl or sulfonic acid modified synthetic latex, 2-4 parts of surfactant, 0.5-1.5 parts of filler, and 75-88 parts of deionized water;

[0005] Further, the synthetic latex is styrene-butadiene latex or chloroprene latex;

[0006] Furthermore, the mass ratio of natural latex to carboxyl or sulfonic acid synthetic latex is 2-3:1;

[0007] Furthermore, the mass ratio of natural latex to carboxyl or sulfonic acid synthetic latex is 2:1;

[0008] Further, the surfactant includes anionic surfactant and nonionic surfactant;

[0009] Furthermore, by weight, 1.0-2.5 parts of anionic surfactant and 0.1-0.3 parts of nonionic surfactant;

[0010] Further, the anionic surfactant is one or more of alkylbenzene sulfonate, alkylnaphthalene sulfonate, and alkyl glyceryl ether sulfonate;

[0011] Furthermore, the nonionic surfactant is one or more of fatty acid glycerides, polyethylene glycol fatty acid esters, and polyethylene glycol;

[0012] Further, the filler is an inorganic filler;

[0013] Further, the inorganic filler is sodium bentonite;

[0014] A method for preparing a green tire external spray liquid comprises the following steps: dissolving a surfactant in deionized water, adding a filler, stirring for 30-50 minutes, grinding, adding natural latex and carboxyl or sulfonic acid modified synthetic latex, and stirring at room temperature for 20-40 minutes;

[0015] Furthermore, natural rubber latex and modified synthetic latex were added and stirred at room temperature for 30 minutes.

[0016] Due to the adoption of the above technical solution, the beneficial technical effects of the present invention are:

[0017] 1. The present invention designs a green tire external spray liquid. The carboxyl or sulfonic acid group modified synthetic latex and natural latex of the green tire external spray liquid are compounded in a certain proportion to play a synergistic role, forming an elastic film that is strongly bonded to the rubber on the surface of the green tire, so that the tire can be easily and completely separated from the mold. The green tire external spray liquid does not contain silicone oil and organic solvents. Compared with the prior art, it does not cause scale to form on the mold surface, and the characteristic structure of the mold surface cannot be clearly printed on the surface of the tire;

[0018] 2. The green tire external spray of the present invention can effectively reduce tire vulcanization defects and make the tire have an excellent appearance. The present invention has a small dosage, a short drying time, is not easy to precipitate, can be sprayed with an air spray gun, and is easy to operate, so it can replace the mold release agent;

[0019] 4. The overall formula of the green tire external spray liquid of the present invention is simple, easy to prepare, low in production cost, and has no pollution to the environment. DETAILED DESCRIPTION

[0020] The following will be combined with the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without making creative work are within the scope of protection of the present invention.

[0021] A green tire external spray liquid comprises, by weight: 8-15 parts of natural latex, 5-8 parts of carboxyl or sulfonic acid modified synthetic latex, 2-4 parts of surfactant, 0.5-1.5 parts of filler, and 75-88 parts of deionized water. Natural latex has good film-forming properties, and the film formed during bonding has high elasticity and flexibility, but its aging resistance and temperature resistance are poor, and its adhesion to the adherend is poor; carboxyl or sulfonic acid modified synthetic latex has smaller particles than natural latex, is aging and high temperature resistant, and has strong bonding ability; a layer of elastic film that is strongly bonded to rubber is formed on the surface of the green tire, so that the tire can be easily and completely separated from the mold. In addition, after the green tire external spray liquid is sprayed on the outer surface of the green tire embryo, it is transparent after vulcanization and does not affect the appearance of the tire.

[0022] The usage ratio of natural rubber latex to carboxyl or sulfonic acid modified synthetic latex is 2-3:1. Natural rubber latex and carboxyl or sulfonic acid modified synthetic latex can be compounded in a certain proportion to play a synergistic role, and after drying, an elastic film with strong adhesion to raw rubber is formed.

[0023] The carboxyl or sulfonic acid modified synthetic latex is carboxyl or sulfonic acid modified styrene butadiene latex or carboxyl or sulfonic acid modified chloroprene latex. The styrene butadiene latex or chloroprene latex is modified with carboxyl or sulfonic acid groups to improve the temperature and salt resistance and is not easy to demulsify; it has good dispersibility with natural latex and is not easy to flocculate.

[0024] Surfactants include anionic surfactants and nonionic surfactants. Anionic surfactants are one or more of alkylbenzene sulfonates, alkylnaphthalene sulfonates, and alkyl glyceryl ether sulfonates. Nonionic surfactants are one or more of fatty acid glycerides, polyethylene glycol fatty acid esters, and polyethylene glycol. Because carboxyl or sulfonic acid group-modified synthetic latex is anion-modified, cationic surfactants are not suitable for this system. Adding surfactants can reduce the surface tension of the product on the rubber surface of the green tire. Anionic surfactants have the effect of dispersing and suspending fillers to maintain the stability of the emulsion; nonionic surfactants are dispersed in the solution and have the functions of lubrication, dispersion, solubilization, and antistatic. The two surfactants are used in combination and have excellent wettability, which helps the green tire external spray to form a complete elastic film on the surface of the green tire. This film can not only play a good isolation effect, but also keep the tire surface bright, antistatic, and not easy to stick to dirt after vulcanization, reducing the use of tire protective agents or tire finishing liquids.

[0025] The filler is an inorganic filler, and sodium bentonite can be selected. Sodium bentonite has good dispersibility in water medium, good suspension lubricity, and good thermal stability. As a filler, it can play a lubricating and isolating effect between the green tire surface and the mold, and provide good air exhaust and in-mold fluidity during the vulcanization process.

[0026] Example 1

[0027] The green tire external spray liquid includes, by mass, 12 parts of natural rubber latex, 6 parts of carboxyl-modified styrene-butadiene latex, 2.5 parts of sodium dodecylnaphthalene sulfonate, 0.1 parts of polyethylene glycol fatty acid ester, 1 part of sodium bentonite, and 78.4 parts of deionized water.

[0028] The preparation steps are as follows:

[0029] Add 78.4 parts of deionized water, 2.5 parts of sodium dodecylnaphthalene sulfonate and 0.1 parts of polyethylene glycol fatty acid ester into a reaction kettle, stir evenly at room temperature, then add 1 part of sodium bentonite and stir for 40 minutes, pass through a grinder and return to the kettle, add 12 parts of natural latex and 6 parts of carboxyl-modified styrene-butadiene latex, and stir at room temperature for 30 minutes to obtain the product.

[0030] Example 2

[0031] The green tire external spray liquid includes, by mass, 15 parts of natural rubber latex, 5 parts of sulfonic acid modified styrene butadiene latex, 1.7 parts of sodium dodecylnaphthalene sulfonate, 0.3 parts of polyethylene glycol fatty acid ester, 0.5 parts of sodium bentonite, and 77.7 parts of deionized water.

[0032] The preparation steps are as follows:

[0033] Add 77.7 parts of deionized water, 1.7 parts of sodium dodecylnaphthalene sulfonate and 0.3 parts of polyethylene glycol fatty acid ester into a reaction kettle, stir evenly at room temperature, then add 0.5 parts of sodium bentonite and stir for 50 minutes, pass through a grinder and return to the kettle, add 15 parts of natural latex and 5 parts of sulfonic acid modified styrene butadiene latex, and stir at room temperature for 40 minutes to obtain the product.

[0034] Example 3

[0035] The green tire external spray liquid includes, by mass, 8 parts of natural rubber latex, 8 parts of sulfonic acid modified chloroprene rubber latex, 2 parts of sodium dodecylbenzene sulfonate, 0.2 parts of polyethylene glycol, 1.5 parts of sodium bentonite, and 88 parts of deionized water.

[0036] The preparation steps are as follows:

[0037] Add 88 parts of deionized water, 2 parts of sodium dodecylbenzene sulfonate and 0.2 parts of polyethylene glycol into a reaction kettle, stir evenly at room temperature, then add 1.5 parts of sodium bentonite and stir for 30 minutes, pass through a grinder and return to the kettle, add 8 parts of natural latex and 8 parts of sulfonic acid modified chloroprene latex, and stir at room temperature for 20 minutes to obtain the product.

[0038] Example 4

[0039] The green tire external spray liquid includes, by mass, 10 parts of natural rubber latex, 6 parts of carboxyl-modified chloroprene rubber latex, 3 parts of dodecylbenzene sulfonic acid, 1 part of polyethylene glycol, 1 part of sodium bentonite, and 75 parts of deionized water.

[0040] The preparation steps are as follows:

[0041] Add 75 parts of deionized water, 3 parts of sodium dodecylbenzene sulfonate and 1 part of polyethylene glycol into a reaction kettle, stir evenly at room temperature, then add 1 part of sodium bentonite and stir for 30 minutes, pass through a grinder and return to the kettle, add 10 parts of natural latex and 6 parts of carboxyl modified chloroprene rubber latex, and stir at room temperature for 30 minutes to obtain the product.

[0042] Comparative Example 1

[0043] The green tire external spray liquid includes, by mass, 6 parts of natural rubber latex, 12 parts of carboxyl-modified styrene-butadiene latex, 2.5 parts of sodium dodecylnaphthalene sulfonate, 0.1 parts of polyethylene glycol fatty acid ester, and 79.4 parts of deionized water.

[0044] The preparation steps are the same as those in Example 1.

[0045] Comparative Example 2

[0046] The green tire external spray liquid includes, by mass, 12 parts of natural rubber latex, 2.5 parts of sodium dodecylnaphthalene sulfonate, 0.1 parts of polyethylene glycol fatty acid ester, 1 part of sodium bentonite, and 84.4 parts of deionized water.

[0047] The preparation steps are the same as those in Example 1.

[0048] Comparative Example 3

[0049] The green tire external spray liquid includes, by mass, 6 parts of carboxyl-modified styrene-butadiene latex, 2.5 parts of sodium dodecylnaphthalene sulfonate, 0.1 parts of polyethylene glycol fatty acid ester, 1 part of sodium bentonite, and 90.4 parts of deionized water.

[0050] The preparation steps are the same as those in Example 1.

[0051] (I) The drying time and post-drying state of the green tire external spray liquid prepared in Examples 1-4 and Comparative Examples 1-3 were tested and analyzed, and the data shown in Table 1 were obtained.

[0052] Table 1 Test results of drying time and post-drying state of green tires prepared by Examples 1-4 and Comparative Examples 1-3

[0053] Drying time / min Apply evenly on the raw film and observe the state after drying Example 1 9 The elastic film formed is difficult to peel off Example 2 9 The elastic film formed is difficult to peel off Example 3 10 The elastic film formed is difficult to peel off Example 4 10 The elastic film formed is difficult to peel off Comparative Example 1 9 The elastic film formed is easy to peel off Comparative Example 2 10 The elastic membrane formed will fall off easily but the membrane is relatively intact. Comparative Example 3 8 The elastic film formed is difficult to peel off but the film is fragile

[0054] As can be seen from the table above, the drying time of the green tire external spray liquid prepared in Examples 1-4 is ≤10min, and the film-forming time is short, which can save production time and cost; after drying, an elastic film with strong adhesion to the raw rubber is formed, indicating that the natural latex and the carboxyl or sulfonic acid group modified synthetic latex in the present invention have an important film-forming effect in synergy. However, the film formed by the green tire external spray liquid prepared in Comparative Examples 2-3 has poor adhesion to the green tire.

[0055] (ii) The green tire external spray liquid prepared in Examples 1-4 and Comparative Examples 1-3 was sprayed on the raw rubber sheet (tread rubber or sidewall rubber), respectively, and placed in a preheated homemade vulcanization mold. The demolding effect was tested by vulcanization on a flat vulcanizer at a vulcanization temperature of 170°C and a vulcanization time of 10 min. After vulcanization, whether the rubber sheet can be easily separated from the mold is observed to judge the isolation effect, and the data shown in Table 2 are obtained.

[0056] Table 2 Isolation effect of external spraying of green tires prepared in Examples 1-4 and Comparative Examples 1-3

[0057] Tread rubber Sidewall rubber Example 1 Good isolation effect Good isolation effect Example 2 Good isolation effect Good isolation effect Example 3 Good isolation effect Good isolation effect Example 4 Good isolation effect Good isolation effect Comparative Example 1 Poor isolation effect Poor isolation effect Comparative Example 2 Poor isolation effect Poor isolation effect Comparative Example 3 Poor isolation effect Poor isolation effect

[0058] It can be seen from the above table that the green tire external spray liquid prepared in Examples 1-4 has good isolation effect on the tread rubber and the sidewall rubber. The reasonable ratio of surfactant and filler makes the isolation effect of the green tire external spray liquid significantly improved compared with the isolation effect of Comparative Examples 1-3.

[0059] (III) Destructive tests to verify air venting and in-mold fluidity.

[0060] The raw rubber sheets were cut into sizes of 1 / 5, 2 / 5, 3 / 5, and 4 / 5 (with equal thickness and width) according to the length of the mold, and then the raw tire external spray samples were sprayed according to Examples 1-4 and Comparative Examples 1-3, respectively. The samples were placed in a preheated homemade vulcanization mold, and the demolding effect was tested on a flat vulcanizer at a vulcanization temperature of 170°C and a vulcanization time of 10 min. The size of the rubber sheet in the mold cavity after vulcanization was observed to determine the in-mold fluidity, and whether there were bulges in the rubber sheet after vulcanization was observed to determine the air discharge property.

[0061] Table 3 Effect of external spraying of green tires prepared in Examples 1-4 and Comparative Examples 1-3 on the degassing properties and in-mold fluidity of raw rubber

[0062]

[0063] It can be seen from the above table that the green tire external spray liquid prepared in Examples 1-4 can provide the raw rubber with good air exhaust and in-mold fluidity. When the raw rubber sheet is cut into 3 / 5, the green tire external spray liquid prepared in Examples 1-4 can make the raw rubber basically cover the mold cavity, while the green tire external spray liquid prepared in Comparative Example 1-3 makes the raw rubber not cover the mold cavity and squeeze out of the mold.

[0064] Therefore, the overall formula of the green tire external spray is simple, easy to make, low in production cost, and can effectively reduce tire vulcanization defects and make the tire have an excellent appearance. The carboxyl or sulfonic acid modified synthetic latex and natural latex are compounded in a certain proportion to play a synergistic role, forming an elastic film that strongly adheres to the rubber on the surface of the green tire, so that the tire can be easily and completely separated from the mold.

[0065] In addition, it should be understood that although the present specification is described according to implementation modes, not every implementation mode contains only one independent technical solution. This description of the specification is only for the sake of clarity. Those skilled in the art should regard the specification as a whole. The technical solutions in each embodiment may also be appropriately combined to form other implementation modes that can be understood by those skilled in the art.

Claims

1. A green tire external spray, characterized in that: The composition comprises, by mass: 8-15 parts of natural latex, 5-8 parts of carboxyl or sulfonic acid modified synthetic latex, 2-4 parts of surfactant, 0.5-1.5 parts of filler, and 75-88 parts of deionized water; The mass ratio of natural latex to carboxyl or sulfonic acid synthetic latex is 2:

1.

2. A green tire external spray according to claim 1, characterized in that: The surfactant includes anionic surfactants and nonionic surfactants.

3. A green tire external spray according to claim 2, characterized in that: By mass, the anionic surfactant is 1.0-2.5 parts, and the nonionic surfactant is 0.1-0.3 parts.

4. A green tire external spray according to claim 3, characterized in that: The anionic surfactant is one or more of alkylbenzene sulfonate, alkylnaphthalene sulfonate and alkyl glyceryl ether sulfonate.

5. The green tire external spray according to claim 2, characterized in that: The nonionic surfactant is one or more of fatty acid glyceride, polyethylene glycol fatty acid ester and polyethylene glycol.

6. A green tire external spray according to claim 1, characterized in that: The filler is an inorganic filler.

7. The green tire external spray according to claim 1, characterized in that: The synthetic latex is carboxyl-modified styrene-butadiene latex.

8. A method for preparing a green tire external spray liquid as claimed in any one of claims 1 to 7, characterized in that: The preparation method comprises the following steps: dissolving a surfactant in deionized water, adding a filler, stirring for 30-50 minutes, grinding, adding natural latex and carboxyl or sulfonic acid modified synthetic latex, and stirring at room temperature for 20-40 minutes.

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