JPS5959733A - Membrane containing liquid active material and production thereof - Google Patents

Abstract

PURPOSE:To produce a membrane having a liquid active material, which can release the liquid active material at a constant rate over a long period of time, by coating the surface of a support with a soln. obtd. by dissolving a polymer and an active material, which is a liquid at room temp., in a specified org. solvent and then evaporating the solvent. CONSTITUTION:At least 30wt% polymer (A) such as PS and not more than 70wt% active material (B) (e.g. diazinon), which is a liquid at room temp. and has a solubility of not more than 5pts.wt. per 100pts.wt. polymer at room temp., are dissolved in an org. solvent (e.g. chloroform) in such a proportion as to give a concn. of 10-40wt% in term s of the combined quantity of components A and B, said solvent being capable of dissolving components A and B and being more volatile than component B. The resulting soln. is applied to the surface of a support in a coating thickness of 10-50mu and evaporated by heating at 0-100 deg.C, but at a temp. not higher than the b.p. of the solvent in an atmosphere having humidity of 60% or above to form a polymer layer in which component B in the formh of liquid droplet is enclosed in a lot of micropores which have a pore size of 0.5-10mu and are divided by a partition wall of 0.5-10mu in thickness.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention provides a film containing a liquid active substance that can be suitably used as a device for releasing a liquid active substance at a substantially constant and controlled rate over a long period of time. Regarding the manufacturing method.

Various devices for controlling the release of active substances are already known, and generally include a carrier layer containing a dissolved hIj substance and a carrier layer surrounding this 1U body layer, and controlling the permeation or release of the active substance. and a control layer that controls diffusion and releases the active substance at a substantially constant rate into the ambient atmosphere. When the active substance is in liquid form, the active substance is usually dissolved and contained in a polymer that is highly compatible with the active substance to form a uniform carrier;
A control layer is formed by surrounding the carrier layer with a polymer having low compatibility with the active substance. However, according to such a device, there is a limit to the solubility of the active substance in the polymer as a layer, and it is usually difficult to contain more than 30% by weight of the active substance. That is, when a liquid active substance is dissolved and contained in a large amount exceeding 30% by weight, the polymer cannot form a solid 71-lix, so the amount of active substance contained is usually 1 OiIXid.
% culm degree.

For this reason, the active substance can be transferred to a porous material with a large number of through-holes.
IX integrated molded article, for example, absorbed into a porous membrane,
A method of using this as a carrier layer has also been proposed, but in this method, since the surface of the carrier layer is covered with an active substance, it is difficult to form a control layer on top of it. )
It is 1 ton, oil-tight, and the carrier layer is enclosed in one model as a control IN, which requires time and effort to manufacture and is expensive.

The present invention has been made to solve the various problems described above, and includes a homogeneous polymer layer having a large number of independent micropores, and a liquid active substance encapsulated in the form of droplets within the micropores. A new liquid/l! f! It is an object of the present invention to provide a substance containing 11 history and a method for its production, and therefore that the membrane according to the invention is suitable for use as a membrane for releasing a liquid active substance at a substantially constant and controlled rate. I can do it.

The liquid active substance-containing membrane according to the present invention has a homogeneous polymer layer having a large number of independent micropores, a limited solubility for the polymer at room temperature, and a droplet formed in the micropores. It is characterized by consisting of an encapsulated liquid active substance.

In the present invention, a liquid active substance refers to a substance that is liquid at room temperature and has chemical or physiological activities such as pesticide activity, attractant activity, repellent activity, and aromatic activity; for example, rather than pesticide active substances, Insecticides such as N, I1ed, Diazinone, Sumithion, β-propiolac 1. Bactericides such as 1-lyethylene glycol 7-hexyl ether, N,N-diethyl-I
TI-1-Lua main 1 repellent, dodecyl acetate-1
-1Z-11-tetradecenyl acetate-I, Z-11
Examples include attractants such as hekiladecenal, limonene, silyl alcohol, esters derived from hydrocarbons having 6 to 16 carbon atoms, ethers, and aromatic active substances such as aldehydes I.

In the liquid active substance-containing membrane according to the present invention, the polymer layer constituting the carrier has a large number of independent molecules, and
It is a porous body that is homogeneous throughout the thickness direction, and the micropores have a pore size in the range of 0.5 to 1/l (1/l) and are partitioned by thin partition walls with a thickness of 0.1 to 5 μm. and are mutually independent.

The liquid active substance is encapsulated in liquid form within these pores and dispersed within the polymer layer. The film thickness is not particularly limited, but is oil-tight and in the range of 10 to 500 μm. Thus, the membranes of the present invention have extremely high porosity and can therefore contain up to 70% by weight LO- of liquid active material.

The back side of the polymer layer is provided with a sheet, ie, a backing material, which prevents the passage of the active substance. It consists of a laminate of these.

In the present invention, it is necessary for the polymer constituting the carrier to have limited solubility for the liquid active substance used, and solubility here means 100 weight 1 of the polymer (1
πIQ'6 refers to the maximum number of parts by weight of liquid active substance that can be obtained, and limited solubility means that the active substance is only soluble within the range of 5 parts by weight 1uF per 10 parts by weight of the polymer. In particular, a polymer that can be dissolved in a range of 0.01 to 1 part by weight is preferably used.

Such polymers are appropriately selected depending on the liquid active substance used, and specific examples include polysulfone,
poly(mec)acrylic acid ester containing polysulfone-1-, polystyrene, polymethylmethacrylate-1,
Polyamide, polyvinylidene chloride, polyvinylidene chloride, cell[=1-suester, regenerated cellulose, polyurethane, polyhinyl alcohol, polyvinyl chloride, polyhinyl acetate, ethylene-vinyl acetate copolymer, vinyl chloride-vinyl acetate copolymer] One or a mixture of two or more of polymers, polystyrene-polybutadiene block copolymers, etc. can be mentioned.

According to the invention, a liquid active substance-containing membrane as described above can be prepared by:
A polymer and an active substance which is liquid at room temperature and which has limited solubility at room temperature when cut into the polymer are capable of dissolving both the active substance and the polymer, and which is more easily volatile than the above-mentioned active substance. This solution was applied to the surface of a suitable support, and the above solvent was applied to the surface of an appropriate support in an atmosphere of 60% or more. It is produced by forming a homogeneous polymer layer having micropores, and placing a liquid substance in the form of droplets into the micropores.

The liquid active substance, polymer and solubility are as described above.

The organic solvent used in the method of the present invention must be able to dissolve both the active substance and the 11χ complex, be more volatile than the active substance, and have a lower d1 point, and must have a lower d1 point than the active substance. It is selected as appropriate depending on the type of coalescence, but specifically, for example, lower aliphatic halogenated hydrocarbons such as methylene chloride, chloride borum, carbon tetrachloride, etc.
Examples include lower aliphatic alcohols such as methanol and ethanol, DI' acid esters thereof, and one or a mixture of two or more of acetonitrile ether, terahitoylofuran, and the like. Preferably.

Lower aliphatic halohydrocarbons such as methylene chloride are used. However, when the liquid active substance is relatively volatile, relatively high boiling point solvents such as dimethylborumamide 1- are also used. be able to.

According to the method of the present invention, a liquid active substance and a polymer are dissolved in a shallow container as described above, and this solution is applied to a suitable support, and a concentration of not less than 60% is added. /!ii! The above organic solvent is evaporated in an atmosphere. The concentration of the combined NU↓ of the liquid active substance and polymer in the solution is usually 10 to 40% by market weight, and preferably It is 15-30% by market weight.

The support constitutes the above-mentioned backing cage, and the above-mentioned sheet or film material is used.

However, if necessary, after drying the polymer solution, remove the support;
f. lI AIl L, backing +A made of a different type of sheet paulownia wood may be used.

Temperature at which the organic solvent is evaporated: 14, usually 0 to 10
0 °C, preferably 15 to 7 (1'C (7+ range tare and the temperature of the Wlfl origin of the solvent. Usually,
Room temperature is fine, but if necessary, use a solvent/! It may be heated to a temperature below the lIi point. It may also be released under reduced pressure. In this way, as the organic solvent is introduced, the liquid active substance is added to the polymer to a limited extent.
'Since only X degrees are converted to Yf, phase molecules ulli are formed between the active substance and the polymer, and a minute liquid of the active substance ty1
or 111 is uniformly dispersed in the combined 7 trix, and tj (
＝゜ζThe polymer is porous with many independent micropores.
j't Ji'i is formed, and the liquid active substance is housed within these micropores. In the present invention, since the solvent is added and evaporated in an I atmosphere, the reason is not necessarily clear, or a thin film-like dense layer is not formed on the film surface.
The porous layer is substantially homogeneous through its thickness. The atmospheric humidity to obtain such a homogeneous film is usually 60% or higher.
, preferably 70% or more.

By this method, as described above, the micropores formed in the heavy 181 body are usually partitioned by partition walls with a thickness of 0.1 to 5 1j, and the pore diameter is 0.5 to 10 μm, so the pores are 30 U7 has a porosity of about ~80% and can contain a liquid active substance of up to about 70% by weight,
For practical purposes, it is appropriate to set it at a maximum of about 50ii%.

If necessary, a control layer consisting of a polymer film may be formed on the surface of the membrane as a carrier in order to control the release of the active substance from the carrier.

The polymer for this control layer is IL! In order to suppress the release of the active substance from the body, a polymer is selected that has a lower solubility in the liquid active substance than the carrier polymer, and typically, for example, polyethylene film or polyethylene terephthalate film is preferably used.

Since the membrane thus obtained has a limited solubility for the liquid active substance or the carrier polymer, the liquid active substance in the micropores can spread into the carrier polymer. are suppressed and thus released into the ambient atmosphere at a substantially constant and controlled rate. In other words, the liquid active substance-containing membrane according to the present invention can be suitably used as a so-called sustained release device for a reservoir of active substances.

Furthermore, according to the liquid active substance-containing membrane of the present invention, for example,
Unlike the above-mentioned porous body with through-holes that is simply impregnated with and absorbed with a liquid active substance, the micropores of the carrier porous layer are independent of each other, so it can be formed into any size or shape. Furthermore, by selecting the carrier polymer, the membrane can be made flexible, and thus can be freely deformed depending on the application.

Examples of the present invention are listed below, but the present invention is not limited to the examples in any way.

Example 1 Z'll-tetra-+'Lr, a type of insect attractant
Add 1 ml of nyl acetate to 10 ml of methylene chloride l'+
'i I'r'+1 and 7
Merlon (manufactured by Mohey Chemical Co.)] g was added and melted at room temperature, and the uniform cold temperature/Ik was 17.

Apply this solution to polyethylene film.
Second, apply a thick layer of 900μ at room temperature, temperature 40℃, humidity 9
Leave it in a 0% atmosphere to evaporate methylene chloride,
A gland with a thickness of about 40 μm containing about 50 m% of attractant was obtained.

Incidentally, the amount of Z-11-radesenal added to the polycarbonate is 0.7 parts.

To illustrate the structure of the liquid active substance-containing membrane according to the invention:
A scanning electron micrograph (2000x magnification) of the cross section after the entire amount of the active substance has been released is shown in FIG. As is clear from Section 1, this crotch is a homogeneous porous membrane that does not have a dense layer on the membrane surface, the micropores in the membrane have a pore diameter of 1 to 5 μm, and the micropore partition walls have a thickness of was 0.2.-0.5μ.

For comparison, the solvent was evaporated at a temperature of 20°C.
A comparative active substance-containing film was obtained in exactly the same manner as above, except that the test was carried out at a humidity of 50%. About this film,
llj after the entire amount of active substance has been released in the same way as in point 1.
i-plane scanning electron lI! A photograph (1000x magnification) is shown in Figure 2. As is clear from ``2 Chronicles 2 Ij', the membrane surface has a dense layer with a thickness of about 4μ, and the micropores in the membrane have a pore diameter of 1 to 5μ, and are very small. The A wall had a thickness of 0.2 to 0.5 μm.

In addition, the membrane according to the present invention described in Section 1 and one sample for comparison were each left in an open atmosphere at a temperature of 30'C, and the amount of active substance released was determined from the weight loss of the membrane.

The results are shown in Figure 3. Furthermore, for comparison, Comparative Example 13 was prepared by impregnating and absorbing the same liquid active substance in commercially available oil-tight soft polyurethane foam, a so-called sponge. For this first model, the amount of active substance released was determined in the same manner as above, and is shown in FIG. 3.

Example 2 Polysulfone (Union Carbide Co., Ltd. 1)-170
0) 1 g in 10 ml of methylene chloride at room temperature
i: After 1T, Z − is a type of insect attractant.
1 ml of 11-1-quizatecenal was added and dissolved at room temperature to obtain a homogeneous solution. This solution was applied to the surface of 1-Pole paper, which was laminated with aluminum foil on the back, to a thickness of 900 μm at room temperature, and left in an atmosphere of 15°C and 70% humidity to evaporate methylene chloride. Thus, a film with a thickness of about 40 μm containing about 50 weight % of the attractant was obtained.

In addition, statement 1 is added to the polysulfone of Z-11-hexatecenal.
18 degrees of suspension is 0.7 part.

For comparison, the evaporation of the solvent was carried out at a temperature of 15
A comparative active substance-containing film C': c fi was prepared in exactly the same manner as above except that the temperature was 50%. Furthermore, for comparison, the same flexible polyurethane foam as Comparative Product B was impregnated with the same active substance y' as above to obtain a comparative product.

Each of the membranes according to the present invention and the comparative membranes described above was left in an open atmosphere at a temperature of 30° C., and the amount of active substance released was determined from the weight loss of the crotch. The results are shown in Figure 4.

Example 3 After dissolving 1 g of polymethyl methacrylate I (manufactured by Rohm Antohaas) at room temperature in methylene chloride 1 OmH, 1 g was dissolved by adding Nare l'iml, a type of insecticide, to 1 g. I got a good night's sleep. Apply a thick layer of 900 μm at room temperature on the surface of Coatpol paper, the back side of which is laminated with aluminum foil, and leave it in an atmosphere of 20°C and 80% humidity to evaporate the solvent and attract. The IM is a film with a thickness of about 40μ containing about 50% by weight of the agent.

The solubility of Nare 1 in polymethyl methacrylate 1 is 1.5 parts.

For comparison, in the above, let's emit a solvent: X! Except that the process was carried out at a temperature of 20"C and a humidity of 50%, the same method as above was used (comparative example product E of a film containing a septic substance was obtained.Furthermore,
A comparative product F was obtained by absorbing the same liquid active substance in the same flexible polyurethane foam as the above-mentioned specific axis product B.

Each of the membranes according to the present invention described in ``3'' and the comparative membranes were left in an open atmosphere at 30'C / 1 degree of blue;
The amount of active substance released was determined from the weight loss of the membrane. The results are shown in Figure 5.

Example 4 Polysulfone (manufactured by Union Carbide) = 170
0) 11. ! 8 t) 'C'/j1? , dimethylform, /J, -7mi I' I (l ml) was dissolved in 1 ml and cooled to room temperature. 1 ml of 1-lyethylene glyc-1-nodotonohequin ether, a type of insect repellent, was added to the garlic. In addition dissolved l!, = l I + −, −
A total volume of 11k was obtained. The back of the bag is aluminum,
-Uh,?・, 7 p) at room temperature on a paperboard surface laminated with 7 blue.

The dimethylformamide was evaporated by applying 900μ of the repellent and leaving it in an atmosphere of 50°C and 80°C to obtain a thick layer of about 40μ containing about 50% by weight of the repellent. Ta.

For comparison, in the above, the solvent was heated to 50°C.
C. An active substance-containing film comparative example G was obtained in exactly the same manner as above, except that the test was carried out at a humidity of 50%. Furthermore, for comparison, the same soft Polyurekne foam as Comparative Product I3 was impregnated with the same liquid material 11 as above to obtain Comparative Product 11.

Each of the membranes according to the invention and one odor (for comparison) described above was left in an open atmosphere at a temperature of 30°C, and the amount of active substance released was determined from the weight loss of the membranes. The results are shown in Figure 6.

[Brief explanation of the drawing]

Figure 1 is a scanning electron micrograph of the first folded surface of the liquid active substance-containing membrane according to the present invention after the entire amount of active substance has been released (magnification: 2000 (+2); Electron microscopy similar to the above of the ljh substance-containing film
The photographs (1000x magnification) and Figures 3 to 6 show the changes over time in the amount of 1j1 and V (V) released from the membrane according to the present invention. This is a graph showing: Figure 1 Figure 3 Kazutoshi ■ (Sunday)

Claims (2)

[Claims] (1) A homogeneous polymer layer having a large number of independent micropores,
has limited solubility for the polymer at room temperature;
1. A liquid active substance-containing membrane characterized by comprising: (1) a liquid/lIj substance enclosed in the micropores as droplets; (2) A polymer and an active substance that is liquid at room temperature and has a limited IM of 1 degree at room temperature with respect to the polymer, can melt both the substance and the polymer, and can dissolve the above active substance. Is it possible to use organic solvents that are more volatile than substances? Then, apply this solution to the surface of an appropriate support (2, 60%
By blowing the solvent in an atmosphere of 2% or more, a homogeneous polymer layer having a large number of independent micropores is formed at 〉-〇, and at the same time, the liquid /,! A method for producing a liquid hIi substance-containing membrane, which comprises encapsulating i substances in the form of droplets.