JPH0434414B2 - - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a method for manufacturing a molded article with sustained release of an antibacterial agent, and more specifically, a method for manufacturing a molded article by a dip molding method using a dipping liquid made of natural rubber latex containing an antibacterial agent. This is a method for producing an antibacterial agent sustained release molded article, which is characterized in that a dipping liquid containing an amphoteric antibacterial agent mixed with a compounded latex made from Positex as a raw material is used as the dipping liquid.

Currently, raw latexes used for dip-molded rubber products include natural rubber latex, chloroprene latex, butadiene-styrene copolymer latex, etc. Among them, natural rubber latex has good moldability and molded products. Because of its excellent physical properties, it is still most commonly used today, and its dip-molded products include gloves such as surgical gloves, cooking gloves, agricultural, industrial, and fishing gloves, toy balloons, hygiene,
The product range is extremely diverse, including various catheters including urinary catheters, nipples for baby bottles, and rubberized cloth.

Natural rubber latex is made by adding 0.3 to 1.0% of ammonia as a preservative to the milky white sap that flows out when a rubber tree is cut, and the composition of this latex is 35 to 40% of rubber hydrocarbons. In addition to containing about 2% protein, other small amounts of less than 1% fatty acids or their esters,
Consists of sterols, complex lipids, sugars, minerals, enzymes, etc. Therefore, in natural rubber latex,
Protein, which is an ampholyte contained in the rubber particles, acts as a type of protective colloid by adsorbing to the surface of the rubber particles, helping to stabilize the floating and dispersion of latex particles. That is, since these rubber particles have a negative charge in weakly acidic and alkaline regions, electrostatic repulsion is generated between the rubber particles and they are stably dispersed without agglomeration. Fresh latex flowing from rubber trees is
It is an almost neutral (PH7.0-7.2) and relatively unstable emulsion. In other words, in tropical regions, when latex is exposed to air, it rapidly turns rancid due to the action of bacteria, reaching a pH of around 5 in 12 to 14 hours, causing natural coagulation. This is because the aqueous phase of the latex contains substances such as proteins, salts, sugars, etc. that are extremely favorable for the growth of bacteria, and the bacteria grow extremely rapidly. Therefore, it is necessary to add an appropriate preservative as early as possible before rancidity progresses, but ammonia is the most suitable preservative because it neutralizes acids and repels bacteria to prevent their proliferation. has been done.
Since ammonia is usually added in an amount of 0.3 to 1.0%, the pH of the latex is maintained at an alkaline level of at least 9 or higher, usually 10 or higher. Currently established as the Japanese Industrial Standard for natural rubber latex.
JIS K 6381 (1982) was established along this line.

Usually, compounded latex used for dip molding is one in which vulcanizing agents, vulcanization accelerators, fillers, softeners, anti-aging agents, PH adjusters, etc. are appropriately blended with the raw material latex as described above. These are maintained or adjusted to maintain alkalinity even after being blended. Therefore, the natural rubber latex commonly used at present is based on negatively charged anionic latex, and almost all of the various dip-molded products are manufactured from these.

When alkyl polyaminoethylglycine hydrochloride, which is widely used as an amphoteric antibacterial agent, is added to these ordinary natural rubber latexes, it gels almost instantly or within a few days at the latest. Therefore, when manufacturing various molded products using the dip molding method on an industrial scale, the long-term storage stability of latex, the so-called pot life, is insufficient. There was a problem that the law was difficult to apply.

Natural rubber latex molding methods include the dipping method, casting method, extrusion method, foam rubber manufacturing method, fiber surface treatment method, fiber adhesion method, etc. However, due to its nature, the dip molding method requires the following methods. There are special manufacturing technology issues. In other words, in the dip molding method, a dipping tank is filled with latex, a dipping mold is immersed in the tank, and the dipping mold is then pulled up to adhere the latex to the dipping mold. In comparison, the amount of latex stored in the dipping tank is overwhelmingly larger, so if the latex gels in the dipping tank, the economic loss is immeasurable.

In view of the above technical problems, the present inventors have developed a method for producing natural rubber molded products from natural rubber latex containing antibacterial agents by dip molding, which is capable of continuous production on an industrial scale. As a result of intensive research with the aim of providing a new manufacturing method, we found that by using a dipping liquid containing a compounded latex made from Positex and a specific amphoteric antibacterial agent, it was possible to achieve the desired purpose extremely efficiently. The present invention was achieved by discovering that the following can be achieved.

That is, the present invention provides a method for manufacturing a molded article by dip molding using a dipping liquid made of natural rubber latex containing an antibacterial agent, in which the dipping liquid is a blended latex made from Positex as a raw material and is expressed by the following general formula (). This is a method for manufacturing an antibacterial agent sustained release molded article, which is characterized by using an immersion liquid containing an amphoteric antibacterial agent.

[In the formula, R ₁ is R(NH CH ₂ CH ₂ ) _o , R ₂ is R
It represents NH CH ₂ CH ₂ or a hydrogen atom, R represents an alkyl group having 8 to 18 carbon atoms, and n is an integer of 1 to 3. ] According to the production method of the present invention, continuous production for three months or more is possible by simply replenishing the lost amount in the dipping tank as appropriate.

More detailed examples of the dip molding method in the present invention include a straight method, an adhesive dipping method (anode method or Teague adhesive method), a thermal dipping method, an electrodeposition dipping method, and the like.

Positex used in the present invention refers to a positively charged latex of rubber particles obtained when the pH is lowered to below 4.7, which is the isoelectric point of proteins as protective colloids adsorbed on rubber particles.
It is also known as acidic latex. This positex can be relatively easily prepared from ordinary natural rubber latex. For example, normal natural rubber latex has a rubber content of 1 to 1
After adding 5% cationic surfactant and/or nonionic surfactant, add acid to adjust the pH to 4.7.
Below, it is preferable to lower it to 3.0 or less to make it acidic. In this case, the acid used may be inorganic acid such as hydrochloric acid, sulfuric acid, or formic acid, depending on the purpose of Positex.
It is appropriately selected from organic acids such as acetic acid and oxalic acid.

The amphoteric antibacterial agent used in the present invention is alkylpolyaminoethylglycine hydrochloride represented by the general formula (). When the number of carbon atoms in R in the general formula () is less than 8 or exceeds 18, or n
is 4 or more, it is not suitable because the antibacterial activity of the antibacterial agent sustainedly released from the molded article is low. General formula ()
Preferred specific examples of the alkyl polyaminoethylglycine hydrochloride represented by are dodecyldi(amikiethyl)glycine hydrochloride in which _the number of carbon atoms in R ₁ is 12, n is 2, and R ₂ is H; 14,
Tetradecyl di(aminoethyl)glycine hydrochloride in which n is 2 and R ₂ is H, the number of carbon atoms in R in R ₁ is 8,
Examples include di(octylaminoethyl)glycine hydrochloride in which n is 1 and R in R ₂ has 8 carbon atoms.
In the present invention, amphoteric antibacterial agents can be used alone or in combination of two or more.

Specific examples of antibacterial agent sustained release molded products produced according to the present invention include catheters including urinary catheters, surgical gloves and other gloves, hand bags, nipples for baby bottles, and ice bags used by patients in hospitals. etc. can be mentioned. All of these are extremely effective in preventing infection from bacteria, fungi, etc. by continuing to release antibacterial agents from their surfaces even during long-term use.

EXAMPLES The present invention will be explained in more detail with reference to Examples below.

Note that "parts" in the examples mean "parts by weight."

Example 1 To 100 parts of an acidic natural rubber latex solution (PH2.8) with a solid content concentration of approximately 60 wt%, 0.4 parts of zinc dimethyldiothicarbamate, 1 part of sulfur, 2.5 parts of zinc white, and 1 part of stearic acid were added, and the mixture was uniformly mixed. A compounded latex containing natural rubber as a main component was obtained by dispersing it in To this mixed latex, 6 parts of dodecyl di(aminoethyl)glycine hydrochloride and 4 parts of tetradecyl di(aminoethyl)glycine hydrochloride as antibacterial agents were added to distilled water.
An immersion liquid was obtained by adding 10 parts of a 10% aqueous solution of alkyl polyaminoethylglycine hydrochloride dissolved in 90 parts of the solution.

When a urinary catheter manufacturing device using the immersion method was operated continuously for three months using the above immersion liquid and replenishing the immersion liquid every day to compensate for the amount lost on that day, the latex in the immersion tank did not form any agglomerates. It was confirmed that the system could operate smoothly without any problems.

In addition, the urinary catheter obtained in this way was immersed in test urine at 37°C for one day.
Bacillus subtilis ATCC 6633 was used as the test bacterium to test the antibacterial activity of test urine using the punch plate method. Furthermore, when we repeated the same antibacterial activity test by replacing the test urine with fresh test urine every day24
Formation of an inhibition circle was observed up to the first day.

Comparative Example 1 When the same antibacterial agent as used in Example 1 was added to alkaline (PH9.8) natural rubber latex having the same composition as in Example 1, and the same antibacterial agent was applied to a continuous manufacturing device for urinary catheters using the dipping method, the results were shown in Table 1. The latex in the bath was completely gelled on the second day.

Example 2 The same experiment as in Example 1 was conducted except that di(octylaminoethyl)glycine hydrochloride was used as the antibacterial agent. As in Example 1, stable continuous operation for 3 months was possible. Furthermore, when the antibacterial activity test was repeated on the obtained urinary catheter in the same manner as in Example 1, formation of an inhibition circle was observed until the 26th day.

Example 3 The same experiment as in Example 1 was conducted except that a 20% aqueous solution of dodecyl di(aminoethyl)glycine hydrochloride was used as the antibacterial agent. As in Example 1, stable continuous operation for 3 months was achieved. was completed. Furthermore, when the antibacterial activity test was repeated on the obtained urinary catheter in the same manner as in Example 1, formation of an inhibition circle was observed up to the 31st day.

Example 4 An experiment was conducted in the same manner as in Example 3 except that octadecyldi(aminoethyl)glycine hydrochloride was used instead of dodecyldi(aminoethyl)glycine hydrochloride. It was possible to operate stably and continuously.

Furthermore, when the same test as in Example 3 was repeated for the obtained urinary catheter, formation of an inhibition circle was observed up to the 19th day.

Example 5 An experiment was conducted in the same manner as in Example 3 except that dodecyltri(aminoethyl)glycine hydrochloride was used instead of dodecyldi(aminoethyl)glycine hydrochloride. As in Example 3, the product was stable for 3 months. It was possible to operate continuously.

Further, when the same test as in Example 3 was repeated for the obtained urinary catheter, formation of an inhibition circle was observed until the 18th day.

Claims (1)

[Scope of Claims] 1. In a method of manufacturing a molded article by dip molding using a dipping liquid made of natural rubber latex containing an antibacterial agent, a blended latex made from Positex as a raw material is mixed with the following general formula () as the dipping liquid. A method for producing an antibacterial agent sustained release molded article, which comprises using an immersion liquid containing the amphoteric antibacterial agent shown below. [In the formula, R ₁ is R(NH CH ₂ CH ₂ ) _o , R ₂ is R
It represents NHCH ₂ CH ₂ or a hydrogen atom, R represents an alkyl group having 8 to 18 carbon atoms, and n is an integer of 1 to 3. ] 2 Amphoteric antibacterial agents are dodecyl di(aminoethyl)glycine hydrochloride and tetradecyl di(aminoethyl)
Glycine hydrochloride or di(octylaminoethyl)
The manufacturing method according to claim 1, wherein the glycine hydrochloride is glycine hydrochloride.