CH615446A5 - Process for the manufacture of a hydrophobic substrate comprising grafted hydrophilic inclusions - Google Patents

Abstract

This process consists in storing volatile products in a hydrophobic substrate comprising polymerised hydrophilic inclusions grafted onto the hydrophobic substrate by immersing the substrate comprising the said inclusions in a polar solvent containing the said volatile products, which consist, for example, of perfumes, repellents, deodorants or insecticides. The substrate thus obtained can be employed for releasing into the atmosphere volatile products such as mosquito-repellent products.

Description

The present invention relates to a process for the inclusion and grafting by volume of hydrophilic compounds inside a hydrophobic substrate, and for storage, in the hydrophobic substrate comprising hydrophilic inclusions, of substances soluble in polar solution and volatile in a gaseous atmosphere, which can then be disseminated in the atmosphere when the hydrophobic substrate comprising the hydrophilic inclusions containing the volatile substances is placed in a gaseous atmosphere.

The invention also relates to the product obtained by this process, that is to say the hydrophobic substrate comprising hydrophilic inclusions containing volatile products.

The main patent N ° 606208 of 1/11/74 relates to a process of inclusion and grafting in volume of hydrophilic compounds inside a hydrophobic substrate according to which the hydrophobic polymerized substrate is immersed in a solution comprising hydrophilic monomers in the presence of at least one polymerization inhibitor and the hydrophobic substrate is irradiated with ionizing radiation to graft and polymerize the hydrophilic inclusions created by the hydrophilic monomers in the substrate, and according to which, in particular, after having obtained the hydrophobic substrate comprising hydrophilic inclusions polymerized, grafted and crosslinked, soluble substances are stored in polar solution by immersing the hydrophobic substrate comprising said hydrophilic inclusions in a solution containing said substances.

According to the main patent, a chemical crosslinking agent can be added to the solution of hydrophilic monomers, or the substrate comprising the hydrophilic grafted and polymerized inclusions can be irradiated with ionizing radiation to crosslink these hydrophilic inclusions.

The products soluble in polar solution, in particular in aqueous solution, which are stored in the hydrophilic inclusions of the hydrophobic substrate according to the method of the main patent, are then released when the hydrophobic substrate comprising the hydrophilic inclinations containing these soluble products in polar solution is available. in virgin, aqueous or other solutions.

However, it has been realized that it would be advantageous to also be able to use hydrophobic substrates comprising hydrophilic inclusions containing substances soluble in polar solution to release products such as perfumes, insecticides or deterrents into a gaseous atmosphere.

It was not obvious to a person skilled in the art that these products which were mounted in solution having penetrated through the meshes of the hydrophobic polymer could be easily released in a gaseous atmosphere.

However, this has been discovered for certain suitable compounds.

The products most easily and most effectively released by evaporation are those with the highest vapor pressure.

Thus, the subject of the present invention is a method of inclusions and of volume grafting of hydrophilic compounds inside a hydrophobic substrate and of storage in said inclusions of a substance soluble in polar solution, according to which one immerses the hydrophobic substrate polymerized in a solution comprising the hydrophilic monomers in the presence of at least one polymerization inhibitor and the hydrophobic substrate is irradiated with ionizing radiation to graft and polymerize the hydrophilic inclusions created by the hydrophilic monomers in the substrate, and according to which , after having obtained the hydrophobic substrate comprising the hydrophilic polymerized inclusions, grafted and crosslinked, substances soluble in polar solution are stored by immersing the hydrophobic substrate with said hydrophilic inclusions in a solution containing said substances, and it is characterized in that the substances soluble in polar solution are volatile substances islands in a gaseous atmosphere. These volatile substances can be perfumes, such as mint, lemongrass essence, caramel, deodorants, insecticides or better still deterrents such as dimethyltoluene, diethyltoluamide, dimethylphthalate, nn-2-diethylethoxybenzamide , 2-ethyl-1-3 hexanediol, citronellal, citronellol, 2-butyl 2-ethyl-1-3 propanediol, nn-2-ethyl-chlorobenzamide, pentachlorophenol, and diisobutyl maleate.

Deterrents are the products of choice to be stored in these hydrophilic inclusions. Indeed, hydrophobic substrates can be worn directly on the skin without in5

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suitable or unpleasant contact since the hydrophobic substrates are inert; the final product releasing into the atmosphere the deterrent (s) thus prevents bites by dissuading the mosquito from landing on the human body during its random flight.

The quantities of deterrents necessary to prevent mosquitoes from attacking in the vicinity of the human body had been found to be extremely low and these very small quantities of deterrents could be volatilized in the atmosphere by a product such as that obtained by the process. of the present invention.

In the case of dimethyltoluene, 0.01 mmol / l of air is sufficient to prevent 90% of mosquitoes from landing on the skin.

In addition, the amount of volatilized products is increased by the heat and humidity of the atmosphere. Thus, the quantity of volatilized products is greater when it is more necessary, since these gaseous, humid and hot atmospheres are those where mosquitoes are the most aggressive, hence a particularly favorable self-regulating effect. Coming out of the bath, for example, evaporation is important; it is then that mosquitoes tend to land on the body to bite the unfortunate bather. It is in this type of atmosphere that the hydrophobic substrate comprising hydrophilic inclusions in which deterrents have been stored is most effective.

These hydrophobic substrates comprising hydrophilic inclusions filled with volatile deterrents can be worn in the form of plates, bracelets, etc.

In the case where perfumes are stored in the hydrophilic inclusions of the substrates, these perfumes can be worn in the form of pearls, earrings, fine tongues applied to the skin, watch bands, etc., that is to say - to say in all the very numerous applications where one can use like basic product a hydrophobic plastic.

In addition, it is possible to give the hydrophobic substrate comprising hydrophilic inclusions a closed pocket-like structure inside which volatile products can be stored in liquid or crystallized form.

In summary, the hydrophobic / hydrophilic products described in the main patent can be used to include volatile compounds according to the present invention.

Other characteristics and advantages of the invention will appear in the following description, of exemplary embodiments, given by way of explanation and in no way limitative.

In fig. 1, 2, 3 and 4 appended, the reduction in weight (in milligrams per day) as a function of the time corresponding to the volatilization in the atmosphere, of a volatile compound contained in the hydrophilic inclusions of a hydrophobic substrate, is shown. . In fig. 1, this compound is a caramel compound and in FIGS. 2, 3 and 4 of the essence of lavender.

It also appeared advantageous to apply the manufacturing technique of Plasthyds (registered trademark relating to hydrophobic substrates comprising hydrophilic inclusions) to a raw polymer for manufacture in the form of granules or plastics.

Example 1:

Conditions for grafting onto granules of ethylene / vinyl acetate copolymer (33% vinyl acetate): irradiation under y-radiation of Cobalt 60 with a dose rate of 0.2 Mrad / h and a dose of 1, 5 Mrad; a grafting solution was used comprising 22.6% ethylene glycol acrylate, 2.5% butyl acrylate, 55% deionized water, 20% ethanol, 1% copper acetate and 0.25% copper powder. Out of 50 granules, the average percentage of grafting by weight, as defined in the main patent, is 73.5%. The rise in aroma for the various products of Table I was carried out on the grafted granules, after the granules were washed with deionized water for 24 h in an ultrasonic tank. Washing is necessary due to the duration of irradiation and the high grafting rate achieved. The results obtained are given in Table I.

Example 2:

On ethylene / vinyl acetate copolymer granules (33% vinyl acetate), ethylene glycol acrylate is grafted under y-radiation of Cobalt 60; the dose rate is 0.17 Mrad / h and the dose is 2.72 Mrad. The grafting solution contains 22.5% ethylene glycol acrylate, 2.5% butyl acrylate, 4% Diapeg (polyethylene glycol diacrylate), 52% deionized water, 18% ethanol, 1 , 5% copper acetate and 0.25% copper powder. The percentage of grafting-crosslinking by weight measured on average on 50 granules is 105%. The inclusion of flavor is carried out after washing the grafted granules for 48 h in permuted water in an ultrasonic tank, in order to remove the copper acetate fixed in the hydrophilic zones.

A concentrated solution of caramel designated commercially as Flavor 80D is stored in the inclusions at room temperature. The ascent time studied varies between 3 and 7 days. The measurement of the release, that is to say the volatilization in the atmosphere, was carried out quantitatively by weighing the granules placed in the air as a function of time. On the curve of fig. 1, the time T (in days) is shown on the abscissa and the weight loss P corresponding to the weight of flavor released per day in milligrams per 50 tablets on the ordinate. In solid lines is shown the weight loss for the granules where the volatile flavoring product (caramel Flavor 80D) has been raised for 7 days and in broken lines the granules where the product has been raised for 3 days. We see, in this example, that the quantity of product released into the atmosphere is substantially constant over time.

Example 3:

- Conditions for grafting onto granules of ethylene / vinyl acetate copolymer containing 33% vinyl acetate:

Co60 irradiation under radiation y:

Dose rate = 0.2 Mrad / h Dose = 3.2 Mrad Temperature = 40 ° C.

Grafting solution:

Ethylene glycol acrylate

24.5

%

Butyl acrylate

2.7

%

Deionized water

60

%

Ethanol BG

21.8

%

Copper acetate

1

%

Powdered copper

0.25%

Approximate percentage of grafting: 75%.

- Ascent:

The grafted granules are immersed for 7 days in lavender essence at room temperature.

The rate of ascent is 300%.

- Release:

Five grafted granules reassembled in lavender essence are put in a dish at room temperature and are weighed regularly to assess weight loss as a function of time.

The results obtained are represented by the release curve of FIG. 2 representing the weight in milligrams released per day as a function of the release time (in days).

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Table I

Summary table of the ascent and release results of the grafted granules:% G = 73.5%

Aroma Concentration Presentation Temperature Time Weight gain Remarks and aroma of ascent of approximate ascent salting in aroma in aroma

Caramel 50% in Flavor 80D solution water permuted in water

Room temperature 2d

2 mg / granule

Weak taste for at least 1 hour. Pale yellow coloring. Medium odor.

Concentrated Caramel Solution

Flavor 80D in water

Room temperature 3 d

3.5 mg / granule

A little more pronounced taste. Darker coloring.

Medium odor.

Caramel Concentrate Flavor 80D

In solution Temperature 4 d 3.3 mg / granule

in ambient water

Left in the air, persistent odor, strong coloring.

Menthol 10 g in 10 cc Glitter Temperature 1 day 5.0 mg / granule

ambient BG ethanol

Taste of mint after a while in the mouth.

Strong odor.

Menthol

10 g in 10 cc of BG ethanol

Glitter

Room temperature 2d

5.5 mg / granule

Strong smell,

pungent taste rapidly diminishing.

4 sheets of drawings

Claims (8)

615,446 2 CLAIM I Method for the inclusion and volume grafting of hydrophilic compounds inside a hydrophobic substrate, according to which the hydrophobic polymerized substrate is immersed in a solution comprising hydrophilic monomers in the presence of at least one polymerization inhibitor and is irradiated by ionizing radiation on the hydrophobic substrate to graft and polymerize the hydrophilic inclusions created by the hydrophilic monomers in the substrate, and according to which, after having obtained the hydrophobic substrate comprising hydrophilic polymerized inclusions, grafted and crosslinked, soluble substances are stored in solution polar by immersing the hydrophobic substrate with said hydrophilic inclusions in a solution containing said substances, characterized in that the substances soluble in polar solution are volatile substances in a gaseous atmosphere. SUB-CLAIMS 1. Method according to claim I, characterized in that the volatile substances are insecticidal or dissuasive chemical substances. 2. Method according to claim I, characterized in that the volatile substances are aromatic chemicals of the perfume type. 3. Method according to claim I and sub-claim 1, characterized in that the volatile substances are chosen from the group comprising: dimethyltoluene, diethyltolu-amide, dimethylphthalate, nn-diethyl-2-ethoxybenzamide, 2 -ethyI-1 -3 hexanediol, citronellal, citronellol, 2-butyl 2-ethyl-1-3 propanediol, pentachlorophenol and diisobutyl-maleate. 4. Method according to claim I, characterized in that the volatile substances are deodorizing chemical substances. CLAIM II Hydrophobic substrate obtained according to the process of claim I. SUB-CLAIMS 5. Hydrophobic substrate according to claim II, prepared by the process according to sub-claim 1. 6. Hydrophobic substrate according to claim II, prepared by the process according to sub-claim 2. 7. Hydrophobic substrate according to claim II, prepared by the process according to sub-claim 3. 8. Hydrophobic substrate according to claim II, prepared by the process according to sub-claim 4.