CN101831091A - Method for improving quality of concentrated natural latex - Google Patents
Method for improving quality of concentrated natural latex Download PDFInfo
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- CN101831091A CN101831091A CN 201010183083 CN201010183083A CN101831091A CN 101831091 A CN101831091 A CN 101831091A CN 201010183083 CN201010183083 CN 201010183083 CN 201010183083 A CN201010183083 A CN 201010183083A CN 101831091 A CN101831091 A CN 101831091A
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Abstract
The invention discloses a method for improving quality of concentrated natural latex, which comprises the following steps of: adding diammonium hydrogen phosphate and ethylene-diamine tetraacetic acid ammonium into fresh natural latex, mixing the natural latex uniformly, standing the natural latex for at least 2 hours, then performing centrifugal concentration on the natural latex according to a conventional production process for concentrating the natural latex, and removing calcium and magnesium ions from the fresh natural latex so as to improve the quality of the concentrated natural latex and improve the anti-oxidation and anti-aging performance of various latex products.
Description
[technical field]
The present invention relates to the Quality Control Technology of concentrated natural latex.
[background technology]
Natural rubber commonly used mainly refers to be divided into natural rubber rubber and concentrated natural latex by a kind of macromolecular material of Brazilian para ruber nature synthetic according to process requirements.Natural rubber latex has excellent elasticity, film-forming properties and mechanical property, therefore, up to the present, at medical assistance apparatuses such as the widely used surgical gloves of medical field, medical catheter, tube for blood transfusion,latex, latex examination glovess, and family planning articles for use condom etc., mainly adopt concentrated natural latex production.
At present, concentrated natural latex mainly adopts centrifugal concentration technology to produce, and as stabilising system, technical indicator meets the regulation of GB " GB/T 8289 concentrated natural latex ammonia are preserved centrifugal or livering latex specification " with ammoniacal liquor.Over past ten years, the following outstanding problem of application facet ubiquity at China's concentrated natural latex, promptly detect data and show that every technical indicator of concentrated natural latex meets the regulation of GB/T 8289 fully, but, adopt revertex to produce latex product according to existing manufacturing technique, when particularly producing various tubing series products by the temperature-sensitive technology, the process operation performance obviously descends.Simultaneously, the mechanical property of the various latex products of being produced, particularly oxygen aging resistance but obviously descend, and have had a strong impact on the production and the application of various latex products.
In order to improve the output of natural rubber, since the mid-90 in last century, China popularizes in an all-round way in each producing region of natural rubber and uses the ethrel stimulant.For this reason, many scientific research personnel suspect that homemade concentrated natural latex process operation performance obviously descends, and adopt that the use of degradation and ethrel stimulant has much relations under the oxygen aging resistance of latex product of concentrated natural latex manufacturing.But ethrel stimulates the genetic expression that does not influence natural rubber biosynthesizing key enzyme, illustrates that ethrel stimulates the biosynthesizing that can not regulate natural rubber, and the yield increase effect behind the use ethrel is relevant with the prolongation binder removal time.Trace analysis finds that the various technical indicators of concentrated natural rubber do not have noticeable change after the employing ethrel stimulant, only have volatile fatty acid number slightly to rise, but still meet the regulation of GB GB/T 8289.Therefore, think that as if the saying that the ethrel stimulant influences quality of concentrated natural latex lack foundation.The volatile fatty acid number of concentrated natural latex raises to some extent behind the ethrel stimulant in view of using, and volatile fatty acid number is limited the quantity of and also wanted harsh more than corresponding international standard among new revised national standard GB/T 8289.But these measures can not improve the process operation performance of concentrated natural latex, also can't improve the oxygen aging resistance of the latex product that adopts the revertex manufacturing.
Generally, the concentrated natural latex of prepared fresh will be stored the production that just can be used for latex product more than 3 months at least.This storage process is called the maturation or the slaking of concentrated natural latex again.The maturation that facts have proved revertex is most important to the production of latex product.Yet, up to the present, also unclear for the mechanism of revertex maturation.The concentrated natural latex that generally believes prepared fresh is through after the maturation, and every technical indicator of latex tends towards stability.Yet, find according to our follow-up study in recent years, in the maturation process of the concentrated natural latex of prepared fresh, be not only that the various technical indicators of concentrated natural latex tend towards stability, the gel structure of revertex also changes simultaneously.Almost do not have gel the fresh natural rubber latex that just collects from rubber tree, produced a certain amount of gel and pass through after centrifugal concentrated processing step such as grade is made concentrated natural latex, content is between 30-50%.These gels also not exclusively are to produce by chemical reaction between the rubber hydrocarbon molecular chain, have the gel of chemically crosslinked bond structure.There is quite a few to form " pseudo-gels " by the Van der Waals force effect.In the storage process of concentrated natural latex, most of " pseudo-gels " changes and changes microgel gradually into.Discover that further the formation of " pseudo-gels " and the magnesium ion in the latex have direct relation (concrete reason is not clear).Magnesium ion content is high more in the fresh natural rubber latex, and the gel content in the concentrated natural latex is just high more.In recent years, the content of the magnesium ion in the homemade concentrated natural latex generally raises, and causes concentrated natural latex " pseudo-gels " content in rising trend, and " pseudo-gels " is difficult to change into microgel in the maturation process.This is likely concentrated natural latex processing characteristics main reasons for decrease.In addition, after revertex was processed into latex product, the content that remains in the metal ion in the latex product also increased thereupon.This is likely one of reason of the oxygen aging resistance decline that causes latex product.
[summary of the invention]
The present invention aims to provide a kind of method that improves quality of concentrated natural latex, thereby improves the processing characteristics of revertex, improves the oxygen aging resistance of various latex products.
The method of raising quality of concentrated natural latex of the present invention, it is characterized in that in fresh natural rubber latex, adding Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium, mix, the centrifugal concentrated production technique of parking after at least 2 hours routinely prepares concentrated natural latex.
In a preferred embodiment, the consumption of Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium is respectively 0.05～0.5% of the dried glue weight of fresh natural rubber latex.
In another preferred embodiment, it is 5% the aqueous solution that described Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium adopted deionized water to be mixed with mass concentration before adding fresh natural rubber latex.
In another preferred embodiment, fresh natural rubber latex of the present invention is derived from Brazilian para ruber.
[key problem in technology point]
The present invention adopt Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium respectively with fresh latex in magnesium, calcium ion react, form water-fast secondary magnesium phosphate and Ca-EDTA, in centrifugal concentration process subsequently, remove, can reduce the gel content in the concentrated natural latex, accelerate the maturation of concentrated natural latex.
[beneficial effect]
Adopt technology of the present invention, under the prerequisite that does not influence existing concentrated natural latex manufacturing process, can remove most calcium ions and magnesium ions in the fresh latex, improve the quality of concentrated natural latex, thereby improve the oxygen aging resistance of various latex products.
[embodiment]
The present invention will be described hereinafter to adopt indefiniteness embodiment.Except as otherwise noted, the umber that hereinafter adopts is weight part.
Embodiment 1
Take by weighing 250 parts of drcs and be the fresh natural rubber latex that 40% ammoniacal liquor is preserved, the ammonium dibasic phosphate aqueous solution that adds 2.0 part 5%, 1 part 5% ethylenediamine tetraacetic acid (EDTA) aqueous ammonium mixes, and the production technique that normal temperature leaves standstill after 1 hour routinely can be carried out centrifugal concentrating.The concentrated natural latex of gained is stored naturally, sampling at quarterly intervals, technology is routinely vulcanized, film forming, wherein 1.0 parts of sulphur dosage, 1.0 parts of zinc diethyldithiocarbamate consumptions, 0.5 part of zinc oxide dosage, and cure conditions is 60 ℃ * 60 minutes.After room temperature is parked 24 hours, add 1.0 part 2,2 '-methylene-bis (4-methyl-6-tert butyl phenol), the gained glued membrane is as follows through the mechanical property of 70 ℃ of aging 72 hours front and back:
The mechanical property of the different period of storage concentrated natural latex sulfuration of table 1 glued membrane
Be the performance after aging in the table bracket.
Embodiment 2
Take by weighing 333 parts of drcs and be the fresh natural rubber latex that 30% ammoniacal liquor is preserved, the ammonium dibasic phosphate aqueous solution that adds 3 part 5%, 1 part 5% ethylenediamine tetraacetic acid (EDTA) aqueous ammonium mixes, and the production technique that normal temperature leaves standstill after 1 hour routinely can be carried out centrifugal concentrating.The revertex of gained is stored naturally, sampling at quarterly intervals, and technology is routinely vulcanized, film forming, wherein 1.0 parts of sulphur dosage, 1.0 parts of zinc diethyldithiocarbamate consumptions, 0.5 part of zinc oxide dosage, cure conditions is 60 ℃ * 60 minutes.After room temperature is parked 24 hours, add 1.0 parts of 2,6 di tert butyl 4 methyl phenols, the gained glued membrane is as follows through the mechanical property of 70 ℃ of aging 72 hours front and back:
The mechanical property of the different period of storage concentrated natural latex sulfuration of table 2 glued membrane
Be the performance after aging in the table bracket.
Embodiment 3
Take by weighing 400 parts of drcs and be the fresh natural rubber latex that 25% ammoniacal liquor is preserved, the ammonium dibasic phosphate aqueous solution that adds 2 part 5%, 1 part 5% ethylenediamine tetraacetic acid (EDTA) aqueous ammonium mixes the production technique that back normal temperature leaves standstill after 1 hour routinely and can carry out centrifugal concentrating.Treated revertex is stored naturally, sampling at quarterly intervals, technology is routinely vulcanized, film forming, wherein 1.0 parts of sulphur dosage, 1.0 parts of zinc diethyldithiocarbamate consumptions, 0.5 part of zinc oxide dosage, and cure conditions is 60 ℃ * 60 minutes.After room temperature is parked 24 hours, add 1.0 part 4,4 '-methylene-bis (2,6 di t butyl phenol), the gained glued membrane is as follows through the mechanical property of 70 ℃ of aging 72 hours front and back:
The mechanical property of the different period of storage concentrated natural latex sulfuration of table 3 glued membrane
Be the performance after aging in the table bracket.
Claims (4)
1. method that improves quality of concentrated natural latex, it is characterized in that in fresh natural rubber latex, adding Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium, after mixing, park after at least 2 hours and carry out centrifugal concentrated getting final product according to the concentrated natural latex production technique of routine again.
2. the method for claim 1 is characterized in that the consumption of Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium is respectively 0.05～0.5% of the dried glue weight of fresh natural rubber latex.
3. method as claimed in claim 3 is characterized in that described Secondary ammonium phosphate and ethylenediamine tetraacetic acid (EDTA) ammonium are dissolved in the deionized water with 5% mass concentration respectively.
4. preparation method as claimed in claim 1 is characterized in that described fresh natural rubber latex is derived from Brazilian para ruber.
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| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| CN 201010183083 CN101831091B (en) | 2010-05-20 | 2010-05-20 | Method for improving quality of concentrated natural latex |
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| Application Number | Priority Date | Filing Date | Title |
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| CN 201010183083 CN101831091B (en) | 2010-05-20 | 2010-05-20 | Method for improving quality of concentrated natural latex |
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| CN101831091A true CN101831091A (en) | 2010-09-15 |
| CN101831091B CN101831091B (en) | 2012-03-07 |
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| CN 201010183083 Expired - Fee Related CN101831091B (en) | 2010-05-20 | 2010-05-20 | Method for improving quality of concentrated natural latex |
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Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105111333A (en) * | 2015-09-29 | 2015-12-02 | 广东海洋大学 | Method for preparing epoxidized natural rubber concentrated latex |
| CN113929977A (en) * | 2021-11-05 | 2022-01-14 | 中国热带农业科学院橡胶研究所 | Ageing-resistant high-strength natural rubber and preparation method thereof |
Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1406987A (en) * | 2001-09-13 | 2003-04-02 | 拜尔公司 | Polymer emulsoid concentrating method |
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2010
- 2010-05-20 CN CN 201010183083 patent/CN101831091B/en not_active Expired - Fee Related
Patent Citations (1)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN1406987A (en) * | 2001-09-13 | 2003-04-02 | 拜尔公司 | Polymer emulsoid concentrating method |
Cited By (2)
| Publication number | Priority date | Publication date | Assignee | Title |
|---|---|---|---|---|
| CN105111333A (en) * | 2015-09-29 | 2015-12-02 | 广东海洋大学 | Method for preparing epoxidized natural rubber concentrated latex |
| CN113929977A (en) * | 2021-11-05 | 2022-01-14 | 中国热带农业科学院橡胶研究所 | Ageing-resistant high-strength natural rubber and preparation method thereof |
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| Publication number | Publication date |
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| CN101831091B (en) | 2012-03-07 |
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