JPH08283308A - Production of natural rubber latex molding containing reduced amount of allergen - Google Patents

Abstract

PURPOSE: To produce, simply and easily at a low cost, a natural rubber latex molding from which allergens have been eliminated to a high degree. CONSTITUTION: A molding is produced by adding protease and a surfactant to a purified natural rubber latex to decompose protein, molding and simultaneously vulcanizing the latex, and washing the resulting molding with an alcohol- water mixture contg. 5-80wt.% alcohol or with water contg. 0.005-0.020wt.% free chlorine to remove allergenic proteins.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a method for producing a natural rubber latex molded product having a reduced allergen-inducing substance,
More specifically, the present invention relates to a method for producing a natural rubber product that is free from the risk of immediate allergy caused by proteins.

[0002]

2. Description of the Related Art Natural rubber latex is widely used industrially as a raw material for foam rubber foam products, gloves, condoms, dipping products such as catheters, adhesives and adhesives. Natural rubber latex is obtained as a sap of rubber trees cultivated in farms such as Hevea brasiliens, and in addition to about 30% rubber, each contains about several% of proteins, fatty acids, polysaccharides, minerals, etc. It contains non-rubber components and is called field latex.

As an industrial raw material, field latex is concentrated and refined until the rubber content becomes about 60%, and 0.2 to 0.7% of ammonia is added to the latex in order to prevent the putrefaction of the latex. The purified natural rubber latex described above is used. As a method for purifying the field latex, for example, a creaming method or a centrifugal separation method can be mentioned. Generally, a centrifugal separation method having a high purification efficiency is used. According to this centrifugation method, the diluted natural latex is concentrated by centrifugation to obtain a purified natural rubber latex having a protein content reduced to about 2 to 3% by weight. About half of the protein remaining in this purified natural rubber latex is water-soluble, and acts as a protective colloid in the latex,
Contributes to the stabilization of latex. Also, the remaining proteins are chemically bound to the rubber particles. The hydrophilic protein bound to the rubber particles contributes to the stabilization of the rubber particles in water, and since the protein itself is easily oxidized, it prevents the oxidation and deterioration of the rubber.

However, in recent years, it has been found that an immediate allergy is caused by using medical devices such as gloves made of natural rubber, and the protein present in the natural rubber is an allergen (hereinafter referred to as allergen). Was found. Further, it is pointed out that allergens include not only proteins contained in natural rubber but also proteins denatured by ammonia added at the time of latex purification.

Since the above-mentioned immediate allergy occurs when a patient who has antibodies in the body by contact with the allergen protein comes into contact with the allergen again, natural rubber products containing this allergen are always used. A person may have many potential patients. There are also reports that the morbidity of medical personnel who regularly use natural rubber surgical gloves and inspection gloves reaches 10%.
Therefore, the US Food and Drug Administration (FDA) works on natural rubber product manufacturers to reduce the proteins in natural rubber, and the problem of immediate allergy caused by the use of natural rubber products is a major social problem. It has become.

[0006]

Although the above-mentioned problems have been pointed out for natural rubber, it is inexpensive and tough.
Further, natural rubber products such as gloves have excellent workability and fit, and no suitable substitute material having such characteristics can be found. Therefore, it is important to produce natural rubber products with reduced allergens.

As a method for reducing the protein which is an allergen, conventionally, the natural rubber latex or the natural rubber product is washed with warm water, immersed in a washing tank for an appropriate period of time, or the surface of the natural rubber product is washed. A method is used in which is treated with a chemical such as chlorine.
However, these methods cannot sufficiently reduce the occurrence of allergies.

On the other hand, Japanese Patent Laid-Open No. 6-56902 discloses that
Proteolytic treatment of field latex or purified natural rubber latex with a combination of one or more surfactants and protease, then diluting it with water and concentrating by centrifugation or ultrafiltration. Discloses a method of obtaining a natural rubber latex with a high degree of protein removal.

However, it is not practically easy to completely remove the allergen by the method described in the above publication. In addition, since it is necessary to repeat dilution and concentration in order to highly refine the natural rubber latex that has been subjected to proteolytic treatment, the yield of the latex will deteriorate and the processability of the latex will also deteriorate. It causes to raise or lower the quality.

Therefore, after vulcanization and molding in a state where non-rubber components such as proteolysis products, proteases and surfactants remain in the natural rubber latex which has been subjected to protein decomposition treatment, a molded product is obtained. It is desired to remove the allergen by washing with. An object of the present invention is to provide a method for inexpensively and conveniently producing a natural rubber latex molded product from which allergen is highly removed.

[0011]

Means and Actions for Solving the Problems The present inventors have added a vulcanizing agent and the like to a desired shape while leaving non-rubber components such as protease, surfactant and proteolysis product remaining. As for the natural rubber latex molded product obtained by vulcanization molding, as a result of diligent research on the cleaning effect with various extraction cleaning liquids, it was found that a specific extraction cleaning liquid efficiently cleans and removes the non-rubber component, Has been completed.

That is, the method for producing a natural rubber latex molded product with reduced allergens according to the present invention is such that a purified natural rubber latex is added with a protease and a surfactant for proteolytic treatment, vulcanized and molded, and then the proportion of alcohol is increased. Is washed with an alcohol-water mixed solution of 5 to 80% by weight. Further, the alcohol-water mixture may contain free chlorine in a proportion of 0.02% by weight or less.

Another production method of the present invention is to add 0.005 to 0.02% by weight of free chlorine after purifying natural rubber latex by adding a protease and a surfactant to it for proteolytic treatment and vulcanizing and molding. It is characterized by washing with water. The method for producing a natural rubber latex molded article with reduced allergens of the present invention includes (1) a step of subjecting a purified natural rubber latex to a proteolytic treatment, (2) a step of vulcanizing the latex subjected to the proteolytic treatment, and
(3) Consists of three steps for washing natural rubber products.

Hereinafter, the present invention will be described in detail in each of the above steps. (1) Proteolytic treatment of purified natural rubber latex As the purified natural rubber latex used in the present invention,
As described above, it means a natural rubber latex whose protein content is reduced to 2-3% by weight by the centrifugation method or the like. This latex can be suitably used regardless of whether it is a high ammonia latex containing a large amount of ammonia or a low ammonia latex containing a small amount of ammonia.

In the proteolytic treatment of the purified natural rubber latex, a protease (proteolytic enzyme) and a surfactant are added to the latex to cause an enzymatic reaction. By this enzymatic reaction, the protein bound to or adsorbed on the rubber particles is decomposed or reduced in molecular weight and transferred to the aqueous layer. Surfactants aid the migration of these proteins to the aqueous layer, stabilize the rubber particles that have become unstable in water due to the decomposition of the proteins bound to the rubber particles, and further cleanse after molding. It is used to assist the cleaning removal of impurities in the process.

As the protease, various conventionally known ones can be used and are not particularly limited, but it is preferable to use an alkaline protease. The protease may be derived from bacteria, filamentous fungi, or yeast, but it is particularly preferable to use yeast-derived protease. Furthermore, if necessary, cellulase, amylase, lipase, esterase and the like can be used in combination.

The amount of the protease added is 0.001 to 1. per 100 parts by weight of the solid content of natural rubber latex.
0 parts by weight is preferred. If the amount of protease added is less than the above range, the protein in the latex cannot be sufficiently decomposed. On the other hand, when the amount exceeds the above range, the activity of the enzyme is lowered and the cost is increased.

As the surfactant, (a) a carboxylic acid type,
Sulfonic acid-based, sulfate-based or phosphate-based anionic surfactants, (b) polyoxyalkylene ether-based, polyoxyalkylene ester-based, polyhydric alcohol fatty acid ester-based, sugar fatty acid ester-based, alkyl polyglycoside -Based or polyoxyalkylene polyglucoside-based nonionic surfactant, (c) amino acid-based,
Betaine-based, imidazoline-based or amine oxide-based amphoteric surfactants can be used. These can be used alone, but two or more kinds may be used in combination.

Specific examples of the anionic surfactant (a) are shown below. Examples of the carboxylic acid type include fatty acid salts, polycarboxylic acid salts, polycarboxylic acid salts, rosin acid salts, dimer acid salts, polymer acid salts, tall oil fatty acid salts,
Examples thereof include polyoxyalkylene alkyl ether acetate and polyoxyalkylene alkyl amide ether acetate.

Examples of the sulfonic acid type include alkylbenzene sulfonate, alkyl sulfonate, alkyl naphthalene sulfonate, naphthalene sulfonate, naphthalene sulfonic acid aldehyde condensate, aryl sulfonic acid aldehyde condensate, alkyl diphenyl ether disulfonate. , Dialkyl sulfosuccinates, α-olefin sulfonates and the like.

Examples of the sulfate ester type include alkyl sulfate ester salts, polyoxyalkylene alkyl sulfate ester salts, polyoxyalkylene alkyl phenyl ether sulfate salts, mono- or di- or tristyrylphenyl sulfate ester salts, polyoxyalkylene mono- or di- or Examples thereof include tristyrylphenyl sulfate ester salt.

Examples of the phosphoric acid ester system include alkyl phosphoric acid ester salts, alkylphenol phosphoric acid ester salts, polyoxyalkylene alkyl ether phosphoric acid ester salts, polyoxyalkylene alkyl phenyl ether phosphoric acid ester salts, polyoxyalkylene mono- or di-acids. Alternatively, tristyrylphenyl ether phosphate salt and the like can be mentioned.

As salts of these compounds, metal salts (N
a, K, Ca, Mg, Zn, etc.), ammonia salt, alkanolamine salt (triethanolamine salt, etc.) and the like. Specific examples of the nonionic surfactant (b) are shown below. Examples of the polyoxyalkylene ether type include polyoxyalkylene alkyl ether, polyoxyalkylene alkylphenyl ether, polyoxyalkylene polyol alkyl ether, polyoxyalkylene mono- or di- or tristyryl phenyl ether. Examples of the polyol include polyhydric alcohols having 2 to 12 carbon atoms such as propylene glycol, glycerin, sorbitol, glucose, sucrose, pentaerythritol and sorbitan.

Examples of the polyoxyalkylene ester type include polyoxyalkylene fatty acid ester, polyoxyalkylene alkyl rosin acid ester and the like. Examples of the polyhydric alcohol fatty acid ester system include fatty acid esters of polyhydric alcohols having 2 to 12 carbon atoms and fatty acid esters of polyoxyalkylene polyhydric alcohols. More specifically, examples thereof include sorbitol fatty acid ester, sorbitan fatty acid ester, glycerin fatty acid ester, polyglycerin fatty acid ester, pentaerythritol fatty acid ester, and the like. Further, these polyalkylene oxide adducts (for example, polyoxyalkylene sorbitan fatty acid ester, polyoxyalkylene glycerin fatty acid ester, etc.) can also be used.

Examples of the sugar fatty acid ester type include sucrose, glucose, maltose, fructose, and fatty acid esters of polysaccharides, and polyalkylene oxide adducts thereof can also be used. Examples of the alkyl polyglycoside type include glucose, maltose, fructose, and sucrose as glycosides, and examples thereof include alkyl glucosides, alkyl polyglucosides, polyoxyalkylene alkyl glucosides, and polyoxyalkylene alkyl polyglucosides. Esters are also included. Also, all these polyalkylene oxide adducts can be used.

Other examples include polyoxyalkylene alkyl amines and alkyl alkanol amides. Examples of the alkyl group in these surfactants include linear or branched saturated or unsaturated alkyl groups having 4 to 30 carbon atoms. Examples of the polyoxyalkylene group include those having an alkylene group having 2 to 4 carbon atoms, for example, the number of added moles of ethylene oxide is 1
It can be about 50 mol. In addition, examples of the fatty acid include linear or branched saturated or unsaturated fatty acids having 4 to 30 carbon atoms.

Specific examples of the amphoteric surfactant (c) are shown below. Examples of the amino acid system include acyl amino acid salt, acyl sarcosinate, acyloylmethylaminopropionate, alkylaminopropionate, acylamidoethylaminohydroxyethylmethylcarboxylate and the like. Examples of betaine include alkyldimethylbetaine, alkylhydroxyethylbetaine, acylamidopropylhydroxypropylammoniosulfobetaine, acylamidopropylhydroxypropylammoniosulfobetaine, ricinoleic acid amidopropyldimethylcarboxymethylammoniobetaine, and the like.

Examples of the imidazoline series include alkyl carboxymethyl hydroxyethyl imidazolinium betaine, alkyl ethoxy carboxymethyl carboxymethyl imidazolium betaine and the like. Examples of amine oxides include alkyldimethylamine oxide.

The amount of the above surfactant added is preferably 0.1 to 10 parts by weight with respect to 100 parts by weight of the solid content of natural rubber latex. When the amount of the surfactant added is less than the above range, the above-mentioned action cannot be obtained. on the other hand,
If the amount exceeds the above range, problems such as instability of the latex and deterioration of the strength of the molded product after vulcanization molding occur such that molding cannot be carried out.

The proteolytic treatment is carried out at a temperature of 5 to 90 ° C., preferably 20 to 60 ° C. for 2 minutes to 24 hours by standing or stirring. The temperature is 90
When the temperature is higher than 0 ° C, the enzyme is rapidly deactivated, and when the temperature is lower than 5 ° C, the reaction of the enzyme is difficult to proceed. The surfactant may be added either during the proteolytic treatment or after the treatment.

During the proteolytic treatment, in addition to the above-mentioned components, a pH adjuster and a dispersant may be used in combination, if necessary. (2) Vulcanization molding The natural rubber latex that has been subjected to proteolytic treatment is used for vulcanization molding as it is without purification.

Various conventionally known methods can be used as the vulcanization molding method. For example, a vulcanizing agent is added to a natural rubber latex that has been subjected to a protein decomposition treatment, and if necessary, a vulcanization aid, a vulcanization accelerator, an antioxidant, a reinforcing agent,
Fillers, plasticizers, softeners, etc. are added, usually 20 to 6
By performing a vulcanization reaction at 0 ° C. for about 0.1 to 24 hours, a partially vulcanized latex (pre-vulcanized latex) can be obtained. Next, this pre-vulcanized latex is molded into a desired shape by dip molding or the like, and post-vulcanization is performed if necessary, whereby a natural rubber latex molded body is obtained.

Examples of the vulcanizing agent used in the vulcanization reaction include sulfur and tetramethylthiuram disulfide (TT). Examples of the vulcanization aid include zinc white and stearic acid. Examples of the vulcanization accelerator include dithiocarbamine hydrochloric acid, thiazoles, thiurams and the like.
Examples of the antiaging agent include phenols such as 2,6-di-t-butyl-p-cresol. (3) Cleaning of natural rubber latex molded product The cleaning liquid used for cleaning the natural rubber latex molded product is (i) alcohol-water mixture, (ii) water containing free chlorine, or (iii) alcohol containing free chlorine. A cleaning liquid consisting of any of the water mixtures is used.

The alcohol content in the cleaning solution (i) is 5 to 80% by weight, preferably 10 to 50% by weight. When the content of alcohol is less than the above range, the effect of washing is low because the ability to swell the deproteinized natural rubber latex molded product is low. On the other hand, even if the alcohol is contained in an amount exceeding the above range, the cleaning effect is not increased, which is disadvantageous in terms of cost.

The cleaning liquid is used in a proportion of about 10 to 1000 g per 1 g of the latex molded body, and the latex molded body is immersed in this solution and left standing or stirred for about 1 to 24 hours for cleaning. The washing temperature may be equal to or lower than the azeotropic point of the washing liquid, but usually 25 to 50 ° C
Is set to The alcohol is an aliphatic alcohol having 1 to 5 carbon atoms or an alcohol in which an alkoxy group is substituted, specifically, methanol, ethanol,
n-propanol, isopropyl alcohol (IP
A), 2-methyl-1-propanol, 2-methyl-2
-Propanol, n-butanol, n-pentanol,
Examples thereof include those substituted with methoxy or ethoxy. Of these, methanol, ethanol,
Isopropyl alcohol (IPA), 3-methyl-3-
Methoxybutanol (MMBA) and the like are preferably used.

The reason why the proteolysis products and the like can be effectively removed by the alcohol-water mixed solution is considered as follows. When a natural rubber latex molded article is washed, as the hydrophilic substance such as hydrophilic protein is removed by washing, the molded article is not swollen with water and the washing effect is reduced. It has an affinity with the molded product and can be washed while maintaining the latex molded product in a swollen state. As a result, it is presumed that effective removal will be possible.

The content of free chlorine in the cleaning solution (ii) is 0.005-0.02% by weight, preferably 0.005-.
It is 0.01% by weight. This cleaning liquid is obtained by blowing chlorine gas into water or adding hypochlorite. The content of free chlorine is measured by putting the washing solution in an aqueous solution containing an excess of potassium iodide and back-titrating the produced iodine with sodium thiosulfate.

The treatment of natural rubber with chlorine water is a technique that has been conventionally used to improve the slipperiness and wearability of gloves made of natural rubber, and may contribute to the reduction of proteins that become allergens. It is known that the content of free chlorine in chlorine water that has been conventionally used is 0.0
It is 6% or more. When washed with such a high-concentration chlorine water, the surface of the rubber molded body is chlorinated and becomes rough and its surface area increases, so that the extraction speed is increased in the initial stage of washing. However, as the chlorination progresses, the rubber surface changes to a material that does not easily undergo molecular movement, or amino acids, which are protein decomposition residues, undergo oxidative polymerization and form a film on the surface of the molded body, which inhibits extraction. As a result, the cleaning effect is reduced. on the other hand,
The cleaning solution of the present invention has a chlorine content of 0.005 to 0.005.
Since it is 0.02% by weight, the above-mentioned deterioration of the cleaning effect due to the progress of chlorination is not observed.

The above-mentioned cleaning liquid is used in a proportion of about 10 to 1000 g per 1 g of the latex molding, and the latex molding is immersed in this and left standing or stirred for about 1 to 24 hours for washing. The washing temperature may be equal to or lower than the boiling point of the washing liquid, but is usually set in the range of 25 to 50 ° C. Further, by increasing the chlorine content when the cleaning temperature is high and conversely decreasing the chlorine content when the cleaning temperature is low, it is possible to optimize the cleaning conditions. When the chlorine content is less than 0.005% by weight, the effect of washing is low because the ability to roughen the deproteinized natural rubber latex molded product is low.

The cleaning liquid of (iii) above contains 0.02% by weight or less of chlorine in the cleaning liquid of (i) above, preferably 0.00
It contains 5 to 0.01% by weight. Thus, (i)
The cleaning effect can be enhanced by adding a trace amount of chlorine to the cleaning liquid. The conditions such as the cleaning temperature when using this cleaning liquid are the same as those for the other cleaning liquids described above.

The method for producing a natural rubber latex molded article of the present invention can be used for producing various forms of natural rubber products such as foam products such as foam rubber and dipping products such as gloves and condoms.

[0042]

【Example】

Examples 1 to 9 and Comparative Examples 1 to 4 (Preparation of Natural Rubber Latex Molded Body) Commercially available high ammonia natural rubber latex (rubber solid content 60%, ammonia content 0.7%) was added to the rubber solid content. Non-ion
Anion complex type surfactant 1% by weight, protease 0.
It was added so as to be 02% by weight, and the enzyme reaction was carried out at 40 ° C. for 24 hours.

Emal E-70C (sodium polyoxyethylene lauryl sulfate) from Kao Corporation was used as the non-ion-anion complex surfactant, and alkaline protease from Kao Corporation was used as the protease. Using the latex subjected to the enzyme reaction as it is as a raw material, 1 part by weight of sulfur, 1 part by weight of zinc oxide, and 0.6 part by weight of zinc di-n-butyldithiocarbamate were added to the rubber content of the latex. Prevulcanization was performed at 24 ° C. for 24 hours. Next, using the obtained pre-vulcanized latex, a glove having an average thickness of a rubber film of 0.25 mm was produced by a dipping method. (Removal of Proteolytic Residue by Washing) The rubber gloves obtained by the above method were cut into 2 cm square pieces and used as a measurement sample, and washing was carried out in 300 g of washing solution per 1 g of sample while gently stirring.

Table 1 shows the composition, cleaning temperature and cleaning time of the cleaning liquids used in Examples 1 to 9 and Comparative Examples 2 to 4 above. In Comparative Example 1, cleaning was not performed. The cleaning liquid used in Comparative Example 2 is pure water.

[0045]

[Table 1]

Examples 10-12, Comparative Examples 5-7 (Preparation of Natural Rubber Latex Molded Articles) The average thickness of the rubber film was 0.2 in the same manner as in Examples 1-9 and Comparative Examples 1-4.
A glove that is 5 mm was made. (Removal of Proteolytic Enzyme by Washing) A 2 cm square sample was prepared in the same manner as in Examples 1 to 9 and Comparative Examples 1 to 4, and was washed using 300 g of the washing liquid per 1 g of the sample.

Examples 10 to 12 and Comparative Examples 6 to 7
Table 2 shows the composition, cleaning temperature and cleaning time of the cleaning solution used in
Shown in In Comparative Example 5, washing was not performed. The cleaning liquid used in Comparative Example 6 is pure water.

[0048]

[Table 2]

Evaluation of cleaning effect The sample before cleaning and the sample cleaned in each of the examples and comparative examples were used in a dried state, and 5 ml of pure water was used per 400 mg of the sample at 40 ° C. Time protein extraction was performed. The extracted protein analogs were measured for absorbance at 750 nm using a direct method that does not cause protein precipitation using a protein quantification kit (Procedure No. P5656) from SIGMA, which uses an improved Lowry reagent, and the amount of protein in the extract was determined as albumin. Was calculated as an albumin-equivalent amount from a calibration curve prepared as a standard substance, and the value converted per sample of the molded product was defined as the residual protein amount of the latex molded product.

The results of the above evaluations are as shown in Table 1 or 2.

[0051]

EFFECTS OF THE INVENTION According to the present invention, vulcanization molding is carried out while leaving the non-rubber component in the natural rubber latex, and then the obtained molded body is washed with a specific cleaning liquid.
It is possible to produce a natural rubber latex molded body from which allergens have been sufficiently removed. Therefore, by using the production method of the present invention, a natural rubber product which does not cause allergies can be produced inexpensively and easily.

 ─────────────────────────────────────────────────── ─── Continuation of the front page (72) Inventor Atsuko Kawasaki 3-3 Yamatedai, Okubo-cho, Akashi-shi, Hyogo (72) Inventor Toshiaki Sakaki 1314, 1314 Yoda, Onoue-cho, Kakogawa-shi, Hyogo (72) Inventor Hayashi Shoji 1334 Minato Minato, Wakayama City, Wakayama Prefecture Kao Corporation Wakayama Laboratory (72) Inventor Eiji Kanamaru 1-19-3 Kandanishikicho, Chiyoda-ku, Tokyo 1 Fuji Latex Co., Ltd.

Claims (4)

[Claims] 1. Purified natural rubber latex is proteolytically treated by adding a protease and a surfactant, vulcanized and molded, and then washed with an alcohol-water mixed solution having an alcohol ratio of 5 to 80% by weight. A method for producing a natural rubber latex molded article having a reduced allergen-inducing substance. 2. The allergen-inducing substance according to claim 1, wherein the alcohol is an aliphatic alcohol having 1 to 5 carbon atoms or an aliphatic alcohol having 1 to 5 carbon atoms substituted with an alkoxy group having 1 to 2 carbon atoms. A method for producing a reduced natural rubber latex molding. 3. The method for producing a natural rubber latex molded product with reduced allergen-inducing substance according to claim 1, wherein the alcohol-water mixed liquid contains free chlorine in a proportion of 0.02% by weight or less. 4. Purified natural rubber latex is added with a protease and a surfactant for proteolytic treatment, vulcanized and molded, and then 0.005 to 0.02% by weight of free chlorine is added.
A method for producing a natural rubber latex molded article having reduced allergens, which comprises washing with water containing water.