阅读说明：本技术 一种氧化类恒粘剂及其恒粘天然橡胶制品及制备方法 (Oxidation-type constant-viscosity agent, constant-viscosity natural rubber product and preparation method thereof ) 是由 李建伟 桂红星 黄红海 戴拓 丁丽 赵立广 宋亚忠 王岳坤 张小妹 于 2019-09-12 设计创作，主要内容包括：本发明涉及天然橡胶初加工技术领域,公开了一种氧化类恒粘天然橡胶的制备方法。将氧化类恒粘剂溶解到水中配制成一定浓度的恒粘剂溶液,将配制好的恒粘剂溶液添加到鲜胶乳中,边加入边搅拌,待胶乳凝固熟化一定时间后再脱水、洗涤、干燥制得恒粘天然橡胶。1000g胶乳中加入200ppm～400ppm恒粘剂,制得的天然橡胶加速贮存过程中华莱士塑性初值的贮存硬化值小于2,门尼粘度的贮存硬化值小于4。该方法采用的氧化类恒粘剂安全无毒,恒粘天然橡胶的制备工艺简单,恒粘效果好,生产成本低。(The invention relates to the technical field of natural rubber primary processing, and discloses a preparation method of oxidized constant-viscosity natural rubber. Dissolving the oxidized constant viscosity agent in water to prepare a constant viscosity agent solution with a certain concentration, adding the prepared constant viscosity agent solution into fresh latex while stirring, dehydrating, washing and drying after the latex is solidified and cured for a certain time to prepare the constant viscosity natural rubber. 200 ppm-400 ppm of a constant viscosity agent is added into 1000g of latex, the storage hardening value of the Wallace plastic initial value in the accelerated storage process of the prepared natural rubber is less than 2, and the storage hardening value of the Mooney viscosity is less than 4. The oxidation-type constant viscosity agent adopted by the method is safe and nontoxic, the preparation process of the constant-viscosity natural rubber is simple, the constant-viscosity effect is good, and the production cost is low.)

1. An oxidizing homoeotaxic agent, characterized in that the oxidizing homoeotaxic agent is selected from inorganic oxidizing agents and/or organic peroxides.

2. The preparation method of the oxidized constant-viscosity natural rubber is characterized by comprising the following steps:

1) completely dissolving the oxidized permanent binder of claim 1 in an aqueous solution to prepare a permanent binder solution for later use;

2) taking a proper amount of fresh latex, adding a constant-viscosity agent solution while stirring, curing for 6-8 h after complete solidification, dehydrating, washing and drying to obtain the constant-viscosity natural rubber.

3. The method for preparing oxidized natural rubber with constant viscosity according to claim 2, wherein the mass concentration of the solution of the constant viscosity agent in the step 1) is 5 to 20%.

4. The method for producing oxidized constant-viscosity natural rubber according to claim 2, wherein in the step 1), the mass concentration of the constant-viscosity agent solution is 5 to 10%.

5. The method for preparing oxidized constant-viscosity natural rubber according to claim 2, wherein 100ppm to 400ppm of the oxidized constant-viscosity agent is added to 1000g of fresh latex in the step 2).

6. The method for producing an oxidized constant-viscosity natural rubber according to claim 2, wherein 200ppm to 350ppm of the oxidized constant-viscosity agent is added to 1000g of the fresh latex in the step 2).

7. The method for preparing oxidized constant-viscosity natural rubber according to claim 1, wherein the inorganic oxidizing agent is one or more selected from the group consisting of hydrogen peroxide, sodium hypochlorite, chlorine dioxide, potassium permanganate, potassium persulfate, phosphorus pentoxide, sodium chlorite, sodium thiosulfate and ammonium oxide.

8. A natural rubber produced by the process for producing an oxidized constant-viscosity natural rubber according to any one of claims 1 to 7.

9. The natural rubber of claim 8, wherein the natural rubber has a Wallace initial Plastic value of less than 2.

10. The natural rubber of claim 8, wherein the natural rubber has a Mooney viscosity storage hardening value of less than 4.

Technical Field

The invention relates to the technical field of natural rubber primary processing, in particular to a preparation method of oxidized constant-viscosity natural rubber.

Background

The natural rubber is gradually hardened in the storage process, the Mooney viscosity of the raw rubber is increased, and product enterprises need to continuously adjust the production process, so that the process consistency of the products is reduced, the production cost of the product enterprises is increased, and the economic benefit is reduced. In order to prevent the natural rubber from hardening in the storage process and improve the quality consistency of the natural rubber. In the production, constant-viscosity natural rubber is mainly prepared by using constant-viscosity agents such as hydroxylamine hydrochloride, hydroxylamine sulfate, 2-mercaptobenzothiazole and the like. Hydroxylamine hydrochloride and hydroxylamine sulfate are low-toxicity substances, which harm the health of workers, and the prepared constant-viscosity natural rubber loses the constant-viscosity effect along with the prolonging of storage time; the constant-viscosity natural rubber prepared from the 2-mercaptobenzothiazole has good constant-viscosity effect, but the 2-mercaptobenzothiazole is difficult to dissolve and is inconvenient to operate in production. Therefore, the research and development of a novel constant viscosity agent which is safe, nontoxic, easy to dissolve, good in constant viscosity effect and low in cost is a problem to be solved urgently at present. The topic group adopts an oxidation constant-viscosity agent to prepare the constant-viscosity natural rubber, and the strong oxidation of an oxidant is mainly utilized to oxidize aldehyde groups on a rubber molecular chain, so that the aldehyde group structure on the rubber molecular chain is changed, condensation and projection between the aldehyde groups on the rubber molecular chain and the aldehyde groups, and between the aldehyde groups and amino acid are prevented, and the hardening phenomenon in the natural rubber storage process is prevented.

The invention aims to develop a novel constant-viscosity agent which effectively solves the problems existing in the use process of hydroxylamine hydrochloride, hydroxylamine sulfate, 2-mercaptobenzothiazole and the like, simplifies the production process of constant-viscosity natural rubber and reduces the production cost of processing enterprises.

Disclosure of Invention

The first aspect of the present invention provides an oxidizing homoeotaxic agent selected from inorganic oxidizing agents and/or organic peroxides.

The second aspect of the invention provides a preparation method of oxidized constant-viscosity natural rubber, which comprises the following steps:

1) completely dissolving the oxidized constant viscosity agent in an aqueous solution to prepare a constant viscosity agent solution for later use;

2) taking a proper amount of fresh latex, adding a constant-viscosity agent solution while stirring, curing for 6-8 h after complete solidification, dehydrating, washing and drying to obtain the constant-viscosity natural rubber.

In one embodiment of the present invention, in the step 1), the mass concentration of the constant viscosity agent solution is 5-20%.

In one embodiment of the present invention, in the step 1), the mass concentration of the constant viscosity agent solution is 5 to 10%.

In one embodiment of the present invention, in the step 2), 100ppm to 400ppm of the oxidation-based constant viscosity agent is added to 1000g of the fresh latex.

In one embodiment of the present invention, in the step 2), 200ppm to 350ppm of the oxidation-based constant viscosity agent is added to 1000g of the fresh latex.

In one embodiment of the present invention, the inorganic oxidizing agent is one or more selected from hydrogen peroxide, sodium hypochlorite, chlorine dioxide, potassium permanganate, potassium persulfate, phosphorus pentoxide, sodium chlorite, sodium thiosulfate, and ammonium oxide.

In a third aspect of the present invention, there is provided a natural rubber produced by the above method for producing an oxidized constant-viscosity natural rubber.

As an embodiment of the present invention, the natural rubber has a Wallace initial plasticity with a storage hardening value of less than 2.

As an embodiment of the present invention, the Mooney viscosity of the natural rubber has a storage hardening value of less than 4.

Has the advantages that:

1. the invention can effectively solve the problems that hydroxylamine hydrochloride, hydroxylamine sulfate, 2-mercaptobenzothiazole and the like are harmful to human health, and the constant viscosity effect is unstable and is difficult to dissolve when in use.

2. The production process is simple, the production process of the natural rubber primary processing plant is not required to be changed, and the prepared constant-viscosity natural rubber has good constant-viscosity effect and can be stored for a long time.

3. The selected oxidation-type constant viscosity agent is safe and nontoxic, low in cost and good in solubility.

Detailed Description

The invention will be further understood by reference to the following detailed description of preferred embodiments of the invention and the examples included therein. Unless defined otherwise, all technical and scientific terms used herein have the same meaning as commonly understood by one of ordinary skill in the art to which this application belongs. To the extent that a definition of a particular term disclosed in the prior art is inconsistent with any definitions provided herein, the definition of the term provided herein controls.

As used herein, a feature that does not define a singular or plural form is also intended to include a plural form of the feature unless the context clearly indicates otherwise. It will be further understood that the term "prepared from …," as used herein, is synonymous with "comprising," including, "comprising," "having," "including," and/or "containing," when used in this specification means that the recited composition, step, method, article, or device is present, but does not preclude the presence or addition of one or more other compositions, steps, methods, articles, or devices. Furthermore, the use of "preferred," "preferably," "more preferred," etc., when describing embodiments of the present application, is meant to refer to embodiments of the invention that may provide certain benefits, under certain circumstances. However, other embodiments may be preferred, under the same or other circumstances. In addition, the recitation of one or more preferred embodiments does not imply that other embodiments are not useful, nor is it intended to exclude other embodiments from the scope of the invention.

The first aspect of the present invention provides an oxidizing homoeotaxic agent selected from inorganic oxidizing agents and/or organic peroxides.

The second aspect of the invention relates to a preparation method of oxidized constant-viscosity natural rubber, which comprises the following steps:

1) completely dissolving the oxidized constant viscosity agent in an aqueous solution to prepare a constant viscosity agent solution for later use;

2) taking a proper amount of fresh latex, adding a constant viscosity agent solution while stirring, curing the latex for 6-8 h after the constant viscosity agent solution is completely solidified, dehydrating, washing and drying to obtain the constant viscosity natural rubber.

As an embodiment of the invention, in the step 1), the mass concentration of the constant viscosity agent solution is 5-20%; more preferably 5-10%; more preferably 10%.

In one embodiment of the present invention, in the step 2), 100ppm to 400ppm of the oxidation-based constant viscosity agent is added to 1000g of the fresh latex.

In one embodiment of the invention, in the step 2), 200ppm to 350ppm of the oxidation-based constant viscosity agent is added into every 1000g of fresh latex; more preferably 350 ppm.

As an embodiment of the invention, in the step 2), the stirring speed is 100-200 r/min.

The coagulation in the present invention may be any method known to those skilled in the art, such as acid coagulation, static coagulation or microbial coagulation, and the static coagulation is mainly used in the present invention.

Constant adhesive

Mooney viscosity is an important measure of the processing and use properties of Natural Rubber (NR) because changes in the Mooney viscosity during storage of NR have a great influence on its use. The NR with constant viscosity is beneficial to simplifying the production process of products, improving the automatic control level, keeping the consistency of the product performance, shortening the plastication time of raw rubber and reducing the energy consumption. Therefore, producing NR with constant viscosity is welcomed by the users. The current preparation of Constant Viscosity NR (CVNR) is generally to add a constant viscosity agent in the production process of NR so that the constant viscosity agent can generate chemical action with aldehyde groups on rubber molecular chains, the aldehyde groups are passivated to inhibit the raw rubber from being stored and hardened, and the Mooney viscosity of NR is kept in a stable range. CVNR's of different Mooney viscosities can be produced using different constant viscosity agents.

As an embodiment of the present invention, the oxidative homoleptic agent is selected from inorganic oxidizing agents and/or organic peroxides.

In one embodiment of the present invention, the inorganic oxidizing agent is one or more selected from hydrogen peroxide, sodium hypochlorite, chlorine dioxide, potassium permanganate, potassium persulfate, phosphorus pentoxide, sodium chlorite, sodium thiosulfate, and ammonium oxide.

As an embodiment of the present invention, the inorganic oxidant is selected from one or more of hydrogen peroxide, sodium hypochlorite, chlorine dioxide, potassium permanganate.

In one embodiment of the present invention, the organic peroxide is one selected from cumene hydroperoxide, di (n-propyl) peroxydicarbonate, tert-amyl peroxypivalate, and tert-amyl perbenzoate.

The oxidation constant viscosity agent is a mixture of potassium permanganate and cumene hydroperoxide.

The field latex of the invention is derived from Hevea brasiliensis.

In a third aspect of the present invention, there is provided a natural rubber produced by the above process for producing an oxidized constant-viscosity natural rubber.

In the invention, in the process of accelerating the storage of the constant-viscosity natural rubber, the storage hardening value of the Wallace plastic initial value of the raw rubber is less than 2, and the storage hardening value of the Mooney viscosity is less than 4.

The technique provided by the present invention will be described in detail below with reference to specific examples.