阅读说明：本技术 一种具有良好干粘性能的氯丁胶乳的制备方法 (Preparation method of neoprene latex with good dry adhesion performance ) 是由 戴祖宏 叶伟 曾维亮 于凯华 于 2019-10-31 设计创作，主要内容包括：本发明属于胶乳制备领域,具体公开了一种具有良好干粘性能的氯丁胶乳的制备方法,包括水相配制、油相配制、助剂配制以及聚合四个步骤,所述助剂配制包括引发剂配制、终止剂配制。水相配制步骤为：在软水中依次加入水玻璃、液碱以及氯化钾。采用本发明的方法,可以制备出具有良好干粘性能的氯丁胶乳。(The invention belongs to the field of latex preparation, and particularly discloses a preparation method of neoprene latex with good dry adhesive property. The water phase preparation steps are as follows: adding water glass, liquid alkali and potassium chloride into soft water in sequence. The neoprene latex with good dry adhesive property can be prepared by adopting the method of the invention.)

1. A preparation method of neoprene latex with good dry adhesive property comprises four steps of water phase preparation, oil phase preparation, auxiliary agent preparation and polymerization, wherein the auxiliary agent preparation comprises initiator preparation and terminator preparation, and is characterized in that: the water phase preparation steps are as follows: adding water glass, liquid alkali and potassium chloride into soft water in sequence.

2. The process according to claim 1 for the preparation of a polychloroprene latex having good dry tack properties, characterized in that: the polymerization comprises the following steps:

s1, adding the oil phase and the water phase in sequence and stirring;

s2, adding an initiator for multiple times;

s3, when the specific gravity of the latex reaches more than 1.10, adding the latex into a termination kettle, deeply rotating for 8-12 hours, and adding a termination agent.

3. The process according to claim 2 for the preparation of a polychloroprene latex having good dry tack properties, characterized in that: the first initiator addition, the polymerization temperature was below 22 ℃.

4. The process according to claim 3 for the preparation of a polychloroprene latex having good dry tack properties, wherein: in the polymerization step, after the aqueous phase is added, an antifreeze is added into the polymerization kettle.

5. The process for the preparation of a polychloroprene latex having good dry tack properties according to claim 4, wherein: the initiator preparation raw materials are potassium persulfate solution and potassium ferricyanide solution.

6. The process according to claim 5 for the preparation of a polychloroprene latex having good dry tack properties, wherein: the preparation of the terminator comprises the following steps:

s1, preparation of terminating agent liquid A

Stirring and heating soft water, adding a nonionic emulsifier into the soft water, cooling after the nonionic emulsifier is completely dissolved, and adding liquid alkali for dissolving;

s2, preparing terminator solution B

Adding benzene, disproportionated rosin emulsifier and anti-aging agent in sequence and then stirring;

s3, mixing

Mixing and emulsifying the terminating agent A liquid and the terminating agent B liquid at 40-45 ℃.

7. The process according to claim 6 for the preparation of a polychloroprene latex having good dry tack properties, wherein: the oil phase preparation step comprises the steps of adding a regulator into chloroprene, and adding a disproportionated rosin emulsifier after the regulator is dissolved.

8. The process according to claim 7 for the preparation of a polychloroprene latex having good dry tack properties, wherein: the nonionic emulsifier is polyoxyethylene ether emulsifier solution.

9. The process according to claim 8 for the preparation of a polychloroprene latex having good dry tack properties, wherein: the antifreezing agent is urea solution.

10. The process according to claim 9 for the preparation of a polychloroprene latex having good dry tack properties, characterized in that: and adding an anti-aging agent at the later stage of the polymerization step.

Technical Field

The invention belongs to the field of latex preparation, and particularly relates to a preparation method of neoprene latex with good dry adhesion performance.

Background

The neoprene latex is a high molecular polymer, belonging to one of neoprene products. The neoprene latex has strong binding power, the neoprene latex can be respectively used for dry bonding and wet bonding according to different use requirements, the dry bonding refers to drying the moisture in the latex after the test piece is glued, the temperature is raised and the bonding is complete when the test piece is hot, and the wet bonding refers to bonding the test piece in a wet state after the test piece is glued, and then the bonding is realized by drying.

Neoprene latex is generally used as a wet bond, but the wet bond has a long time course from bonding to bonding, bonding efficiency is low, and many bonding materials require excellent dry bonding performance. The water glass can effectively improve the initial viscosity of the neoprene latex, so that the latex has good dry viscosity. However, if the neoprene latex is added at a later stage, the neoprene latex can release hydrogen chloride in the storage process, water glass can form floccules, precipitates are generated, the stability of the neoprene latex is reduced, and meanwhile, the service performance is also sharply reduced, so that good dry-adhesion performance can be obtained only by mixing and using the neoprene latex. In order to overcome the above-mentioned drawbacks, the applicant has developed a process for preparing a polychloroprene latex having good dry tack properties.

Disclosure of Invention

The invention aims to provide a preparation method of neoprene latex with good dry adhesion performance.

In order to achieve the purpose, the basic scheme of the invention is as follows: a preparation method of neoprene latex with good dry adhesive property comprises four steps of water phase preparation, oil phase preparation, auxiliary agent preparation and polymerization, wherein the auxiliary agent preparation comprises initiator preparation and terminator preparation, and the water phase preparation step is as follows: adding water glass, liquid alkali and potassium chloride into soft water in sequence.

The theory of operation and the beneficial effect of this basic scheme lie in:

the neoprene latex can release hydrogen chloride in the storage process, so that the pH value of the neoprene latex is reduced, floccules can be formed by adding water glass, the stability of the latex is reduced, and meanwhile, the service performance is also sharply reduced. The water glass is a good material for improving the initial viscosity of the latex, so the neoprene latex and the water glass are mixed when the adhesive is manufactured, and the neoprene latex and the water glass are prepared and used.

The application breaks through the conventional method, and the water glass is added when the water phase is prepared, namely, floccules formed by the water glass in the emulsification stage are wrapped on the surfaces of the micelles to form protective colloid together with the micelles, so that no floccules are generated in the later storage process. In addition, potassium chloride is used as an electrolyte, so that formed micelles are smaller, the color of the latex is whiter, and the stability is better.

Further, the polymerization comprises the steps of:

s1, adding the oil phase and the water phase in sequence and stirring;

s2, adding an initiator for multiple times;

s3, when the specific gravity of the latex reaches more than 1.10, adding the latex into a termination kettle, deeply rotating for 8-12 hours, and adding a termination agent.

Has the advantages that: the initiator is added for a plurality of times, so that the polymerization reaction is continuously and stably carried out.

Further, the first initiator addition was carried out at a polymerization temperature of less than 22 ℃.

Has the advantages that: at this temperature, the polymer can be made more crystalline.

Further, in the polymerization step, after the addition of the aqueous phase, an antifreeze agent is added to the polymerization vessel.

Has the advantages that: in the process, the antifreezing agent is added at the early stage of polymerization, so that higher solid content can be prepared, and the phenomenon that the water brought in during the later stage of addition is too large is avoided.

Further, the initiator preparation raw materials are potassium persulfate solution and potassium ferricyanide solution.

Has the advantages that: the potassium ferricyanide is used as an activating agent, the addition of the activating agent can reduce the reaction activation energy, and the generation of free radicals is promoted at a lower temperature, so that the initiation of polymerization reaction is facilitated.

Further, the preparation of the terminator comprises the following steps:

s1, preparation of terminating agent liquid A

Stirring and heating soft water, adding a nonionic emulsifier into the soft water, cooling after the nonionic emulsifier is completely dissolved, and adding liquid alkali for dissolving;

s2, preparing terminator solution B

Adding benzene, disproportionated rosin emulsifier and anti-aging agent in sequence and then stirring;

s3, mixing

Mixing and emulsifying the terminating agent A liquid and the terminating agent B liquid at 40-45 ℃.

Has the advantages that: the terminating agent is prepared by a first solution and a second solution, so that a stable emulsion can be formed, and the stability of the latex can be provided by adding the nonionic emulsifier during the preparation.

Further, the oil phase preparation step comprises the steps of adding a regulator into chloroprene, and adding a disproportionated rosin emulsifier after the regulator is dissolved.

Has the advantages that: the addition amount of the regulator can make the molecular weight of the polymer within the range meeting the requirement of latex adhesive property.

Further, the nonionic emulsifier is polyoxyethylene ether emulsifier solution.

Has the advantages that: good emulsifying effect, low price and convenient preparation.

Further, the antifreeze is urea solution.

Has the advantages that: the price is cheap and the preparation is convenient.

Further, an anti-aging agent is added at the later stage of the polymerization step.

Has the advantages that: the aging resistance of the latex is ensured.

Detailed Description

The following is further detailed by way of specific embodiments:

table 1 shows the composition settings of the raw materials in examples 1-6, the units are parts by weight:

TABLE 1

The following will describe in detail a method for producing a high gel type adhesive polychloroprene latex, taking example 1 as an example.

A method for preparing neoprene latex with good dry adhesion performance comprises the following steps:

A. preparation of aqueous phase

Adding soft water into the water phase preparation tank, adding water glass, sodium hydroxide and potassium chloride into the soft water in sequence under stirring, and circulating by using a pump to completely dissolve the additives in the soft water to obtain a water phase liquid. Then sampling and analyzing to be qualified for later use.

Starting a water phase pump to convey the prepared water phase liquid to a water phase metering tank, closing the water phase feeding cock when the required dosage is reached, stopping the pump, heating to 26-30 ℃ by using steam, and then supplementing dilution water (including steam condensate water), so that the emulsifying effect is ensured and the utilization rate of the water phase preparation tank is improved.

B. Oil phase preparation

Pressing chloroprene into the oil phase preparation tank by nitrogen, then starting stirring, heating to 16-18 ℃, adding butadiene for dissolving for 15 minutes, and then adding disproportionated rosin for dissolving for 25 minutes.

C. Preparation of auxiliary agent

C1, initiator preparation

Preparing a potassium persulfate solution: in a clean preparation barrel, metering soft water, heating to 30-38 ℃, adding potassium persulfate, stirring and dissolving completely for later use.

Preparing a potassium ferricyanide solution: in a clean preparation barrel, soft water is measured well, potassium ferricyanide is added at normal temperature, and the mixture is stirred and dissolved completely for later use.

C2, preparation of terminator

Preparation of a terminator solution A: adding soft water into a terminator preparation tank, starting stirring, heating to 70-80 ℃, and then adding a nonionic emulsifier, wherein in the embodiment, the nonionic emulsifier is polyoxyethylene ether emulsifier solution, or polyoxyethylene fatty alcohol ether emulsifier, after dissolution, cooling to 40-50 ℃, and then adding sodium hydroxide, and dissolving for 20 minutes for later use.

Preparing a terminator solution B: in a clean preparation barrel, benzene is measured, and then disproportionated rosin and an anti-aging agent are sequentially added, wherein in the embodiment, the anti-aging agent is 2, 6-di-tert-butyl-4-methylphenol, and is completely stirred and dissolved.

Adding the prepared terminator B liquid into the terminator A liquid in the preparation tank, and mixing and emulsifying the A liquid and the B liquid at 40-45 ℃ for 40-60 minutes.

C3, antifreeze agent preparation

In a clean preparation barrel, metering soft water, heating to 45-60 ℃, adding urea, stirring and dissolving completely for later use.

D. Polymerisation

After the equipment is checked to be intact, the oil phase is firstly put in, then the water phase is put in, the time is taken for stirring for 10 minutes, then the urea solution is added into the polymerization kettle, and the emulsification is carried out for 20 minutes. Controlling the temperature in the polymerization kettle at 17-24 ℃, measuring the pH value, adding 50 liters of a first initiator, wherein the temperature is required to be less than 22 ℃, measuring the specific gravity once per hour after the polymerization reaction starts, observing the reaction condition in the polymerization kettle by an operator when the specific gravity reaches 1.060, and adding a second initiator if the polymerization speed in the polymerization kettle is low. The method comprises the steps of regulating saline water, controlling the polymerization temperature, sampling and analyzing the total solid content when the specific gravity reaches more than 1.10, putting the mixture into a termination kettle for deep turning, wherein deep turning refers to deep conversion, and means that residual chloroprene monomers are further polymerized under the condition of thermal insulation, deep turning is carried out for 10 hours, the deep turning temperature is 30-35 ℃, sampling and analyzing the total solid and the residual monomers, adding a terminator and stirring for 40 minutes after deep turning when the residual chloroprene monomer content is less than 0.5%, sampling and measuring the pH, and putting the mixture into a storage tank and packaging after stirring for 20 minutes when the pH is more than 11.

To fully illustrate the dry tack and stability properties of the neoprene latex having good dry tack properties prepared in examples 1-6, two additional sets of comparative examples are illustrated, comparative examples 1-3:

comparative example 1 is: domestic similar neoprene latex products (model: SN 5042).

Comparative example 2 is: foreign neoprene latex products of the same type (model: Neprene 572).

Comparative example 3 is: the difference from example 1 is that: no water glass was added to the aqueous phase preparation of step A.

The experimental tests of the above examples 1-6 and comparative examples 1-3 were carried out, and the test methods and results were as follows:

and (3) measuring the peel strength: the dry tack cloth-cloth peel strength was measured according to GB532-82 "method for measuring adhesion Strength of vulcanized rubber to Fabric".

The stability of the polychloroprene latex was examined by measuring the amount of gel produced under high-speed stirring, according to the standard SH/T1151-1992 (confirmed in 1998) for the determination of the high-speed mechanical stability of the synthetic latex, the results of which are shown in Table 2 below:

TABLE 2

From the detection results of table 2 above, it can be seen that:

1. examples 1-6 produced neoprene latex with high peel strength and no gel formation, especially example 4, which had peel strength exceeding that of similar neoprene latex products abroad, and produced neoprene latex products with low cost and good performance.

2. Compared with domestic similar neoprene latex products (comparative example 1), the neoprene latex has low peel strength, and simultaneously has a trace amount of gel, so that the stability of the latex is required to be improved, and the peel strength of the neoprene latex products obtained in the comparative example 3 is further reduced because water glass is not added.

The foregoing is merely an example of the present invention and common general knowledge of known specific structures and features of the embodiments is not described herein in any greater detail. It should be noted that, for those skilled in the art, without departing from the structure of the present invention, several changes and modifications can be made, which should also be regarded as the protection scope of the present invention, and these will not affect the effect of the implementation of the present invention and the practicability of the patent.