Gas mask exhalation valve suitable for low-temperature environment and preparation method of gas mask exhalation valve

Abstract

The invention relates to an exhalation valve for a gas mask and a preparation method of the exhalation valve, the exhalation valve provided by the invention adopts natural rubber as a main body material, natural rubber mixed rubber is prepared, a low-temperature-resistant hydrophobic membrane material subjected to surface treatment is laid on one side of the mixed rubber, then the mixed rubber subjected to film coating treatment is put into a mold to be vulcanized, and the film-coated exhalation valve is obtained. The prepared exhalation valve is good in elasticity and free to open and close, and due to the fact that the hydrophobic film layer is arranged on the surface, when the exhalation valve is used in the plateau low-temperature environment, the phenomenon that water vapor is condensed on the surface of the exhalation valve due to the temperature difference relation when hot air generated when a human body rapidly breathes makes contact with purified external cold gas is avoided, and the exhalation valve is safe and reliable. Water vapor can rapidly drip through the hydrophobic mask layer of the exhalation valve and then flow out through the small holes in the chin of the gas mask, and therefore the problem that an exhalation valve of a common gas mask is prone to icing due to water vapor breathing can be effectively solved.

Description

Technical Field

[0001] The invention belongs to the technical field of composite material preparation, and in particular relates to an exhalation valve for a gas mask suitable for use in a low-temperature environment and a preparation method thereof. Background Art

[0002] When gas mask equipment is used in a low-temperature environment on the plateau, when the hot air generated by the human body's rapid breathing comes into contact with the purified cold external gas, the temperature difference between the exhaled gas and the inhaled gas causes water vapor condensation on the surface of the exhalation valve. Since the water vapor cannot be discharged in time, more and more water vapor accumulates over time. Under extremely low temperature conditions, the water vapor on the exhalation valve quickly freezes. Not only does the exhalation valve become hard, but the ice problem makes it impossible for the exhalation valve to fit tightly with the exhalation valve seat, causing the exhalation valve to fail and become unusable, thereby affecting the safety of the gas mask, and the safety of the user and the reliability of the equipment cannot be guaranteed. Summary of the invention

[0003] In view of the problem that the exhalation valve of the existing gas mask becomes hard and easily freezes due to the accumulation of breath water vapor in a low-temperature environment, thus becoming unusable, the present invention provides an exhalation valve for a gas mask suitable for use in a low-temperature environment, comprising an exhalation valve body and a hydrophobic layer; the exhalation valve body is an umbrella-shaped structure, comprising an exhalation valve umbrella surface and an exhalation valve umbrella handle; the inner side of the exhalation valve umbrella surface is provided with a hydrophobic layer; the exhalation valve body is made of natural rubber, and the hydrophobic layer is one of ETFE or FEP hydrophobic film materials.

[0004] The exhalation valve umbrella handle is provided with a groove for fixing the exhalation valve seat.

[0005] The thickness of the exhalation valve umbrella is 0.45-0.5 mm, and the thickness of the hydrophobic layer is 25-75 μm.

[0006] The exhalation valve is prepared by vulcanizing a natural rubber compound and a hydrophobic film material; the side of the hydrophobic film material that is in contact with the exhalation valve umbrella surface is surface treated; the surface treatment method is a modifier treatment and a plasma activation treatment.

[0007] The modifier is prepared from sodium, naphthalene and solvent in a mass ratio of 1-3:5-10:75-180; the solvent is a mixture of solvent A and solvent B in a mass ratio of 1:0.5-2; the solvent A is one or more of N-methylmorpholine, tetrahydropyran, 2-methyltetrahydrofuran or dioxane, and the solvent B is tetrahydrofuran.

[0008] The plasma activation method is as follows: argon is used as the reaction gas, the gas flow rate is 0.1-0.3 L / min, the discharge voltage is 1.5-4 kV, the frequency is 2-5 kHz, the working distance is 5-8 mm, and the plasma activation layer is formed on the surface of the film material after plasma discharge for 2-6 minutes.

[0009] The natural rubber compound has the following proportions: 100 parts of natural rubber, 5-12 parts of zinc oxide, 1-3 parts of stearic acid, 4-8 parts of carbon black, 1-3 parts of vaseline, 8-15 parts of filler, 2-5 parts of antioxidant, 1.2-2.5 parts of accelerator and 0.8-1.5 parts of vulcanizer.

[0010] The natural rubber is No. 1 smoked sheet rubber.

[0011] The filler is a sulfate, including one or more of ammonium sulfate, ferric sulfate or sodium sulfate; the antioxidant is a mixed preparation of an amine antioxidant and a wax antioxidant, the weight ratio of the amine antioxidant and the wax antioxidant is 3:2, wherein the amine antioxidant includes any one of antioxidant D, antioxidant RD or antioxidant 4010NA, and the wax antioxidant includes any one of paraffin, ozokerite or microcrystalline wax; the accelerator is a mixed preparation of thiazoles and sulfonamides, the weight ratio of the accelerators is 3:8, wherein the thiazole accelerator includes any one of accelerator DM, accelerator M or accelerator MH; the sulfonamide accelerator includes any one of accelerator CZ, accelerator NOBS or accelerator DZ, and the vulcanizing agent is sulfur.

[0012] The present invention also provides a method for preparing an exhalation valve of a gas mask suitable for use in a low temperature environment, comprising the following steps: Preparation of the modifier: adding a solvent and naphthalene into a reaction container and stirring to dissolve, then adding sodium and continuing to stir and react to obtain the modifier; Membrane surface treatment: Plasma activation and modifier treatment are performed on one side of the membrane material in sequence to obtain a modified membrane material; Preparation of natural rubber mixed rubber sheet: mixing according to the ratio of 100 parts of natural rubber, 5-12 parts of zinc oxide, 1-3 parts of stearic acid, 4-8 parts of carbon black, 1-3 parts of vaseline, 8-15 parts of filler, 2-5 parts of antioxidant, 1.2-2.5 parts of accelerator and 0.8-1.5 parts of vulcanizing agent to obtain a mixed rubber sheet; Preparation of the exhalation valve: the surface-treated side of the modified membrane material is tightly fitted with the mixed film to obtain a coated film; the coated film is cut to be slightly larger than the exhalation valve mold position by 5-7mm, and when filling, a small piece of uncoated film that is slightly smaller than the exhalation valve umbrella handle by 0.5-1mm is first cut to fill the hole position of the exhalation valve umbrella handle, and then the coated film is spread to the vulcanization area of ​​the exhalation valve to ensure that the coated side is close to the side of the exhalation valve umbrella handle, and then the mold is closed, and pressurized vulcanization is performed to obtain the exhalation valve; wherein, the vulcanization temperature is: 148-154℃, the vulcanization time is 8-10min, and the vulcanization pressure is 7-10MPa.

[0013] The beneficial effects of the present invention are as follows: The exhalation valve prepared by the present invention has good elasticity and can be opened and closed freely. Moreover, because there is a hydrophobic film layer on the surface, when it is used in a low-temperature environment of a plateau, when the hot air generated by the rapid breathing of the human body contacts the cold external gas after purification, water vapor condensation will not occur on the surface of the exhalation valve due to the temperature difference. The water vapor can drip quickly through the hydrophobic film layer of the exhalation valve and then flow out through the small holes at the chin of the gas mask, thereby effectively solving the problem that the exhalation valve of an ordinary gas mask is easy to freeze due to the exhaled water vapor. The present invention improves the bonding force between the film material and the rubber by surface treating the hydrophobic film material without using an additional adhesive, ensures the mechanical strength of the coated film, and improves the service life of the exhalation valve. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 Axial cross-sectional view of the exhalation valve of the present application; Figure 2 The main view of the exhalation valve of this application; Figure 3 Isometric view of the exhalation valve axis of the present application; Figure 4 A top view of the exhalation valve of this application; Markings in the figure: 1. exhalation valve body, 2. hydrophobic layer, 3. groove, 101. exhalation valve umbrella surface, 102. exhalation valve umbrella handle. DETAILED DESCRIPTION

[0015] The embodiments of the present invention will be described in detail below with reference to examples. The following examples are only used to illustrate the present invention and should not be construed as limiting the scope of the present invention.

[0016] The present invention provides an exhalation valve for a gas mask suitable for use in a low-temperature environment, comprising an exhalation valve body 1 and a hydrophobic layer 2; the exhalation valve body 1 is an umbrella-shaped structure, comprising an exhalation valve umbrella surface 101 and an exhalation valve umbrella handle 102; the inner side of the exhalation valve umbrella surface 101 is provided with the hydrophobic layer 2; the exhalation valve body 1 is made of natural rubber, and the hydrophobic layer 2 is one of ETFE or FEP hydrophobic film materials.

[0017] The exhalation valve umbrella handle 102 has a groove 3 for fixing the exhalation valve seat.

[0018] The thickness of the exhalation valve umbrella 101 is 0.45-0.5 mm, and the thickness of the hydrophobic layer 2 is 25-75 μm.

[0019] The No. 1 cigarette sheet rubber used in the examples of the present application comes from Indonesia, the antioxidant 4010NA comes from Zhejiang East Rubber Additive Co., Ltd., the accelerator DM comes from Zhejiang East Rubber Additive Co., Ltd., the accelerator CZ comes from Zhejiang East Rubber Additive Co., Ltd., ETFE comes from Suzhou Qianmi Technology, FEP comes from Suzhou Qianmi Technology, and Lide powder comes from Xiangtan Hongyan Chemical Co., Ltd.

[0020] Example 1 Preparation of mixed film: 100 parts of No. 1 smoked sheet rubber, 10 parts of zinc oxide, 2 parts of stearic acid, 6 parts of carbon black, 1.5 parts of vaseline, 12 parts of lead powder, 1.5 parts of amine antioxidant 4010NA, 1 part of wax antioxidant paraffin, 0.6 parts of accelerator DM, 1.6 parts of accelerator CZ, and 1.2 parts of sulfur are mixed and mixed evenly to obtain a film with a thickness of 2 mm.

[0021] Preparation of the modifier: N-methylmorpholine, tetrahydrofuran and naphthalene are added into a reaction vessel in a mass ratio of 50:25:5 and stirred until all dissolved, then sodium is added and the stirring reaction is continued. The reaction temperature is controlled at 20°C and the stirring reaction is carried out for 2 hours to obtain a modifier in which the mass ratio of sodium:naphthalene is 1:5.

[0022] Surface treatment of hydrophobic membranes: Place a 25μm thick ETFE membrane on the stage of a plasma treatment device, introduce argon as a reaction gas into the device, control the gas flow rate to 0.1L / min, the discharge voltage to 2kV, the frequency to 2kHz, the working distance to 5mm, and form a plasma activation layer on the membrane surface after plasma discharge for 2min. Then, soak the activated side in a modifier for 1min, and clean it with water and ethanol to obtain a modified membrane.

[0023] Preparation of the exhalation valve: the surface-treated side of the modified membrane material is tightly fitted with the mixed film to obtain a coated film; the coated film is cut to be slightly larger than the exhalation valve mold position by 5~7mm, and when filling, first cut a small piece of uncoated film that is slightly smaller than the exhalation valve handle by 0.5~1mm and fill it into the hole of the exhalation valve umbrella handle, and then spread the coated film to the vulcanization area of ​​the exhalation valve, ensuring that the coated side is close to the side of the exhalation valve umbrella handle, and then close the mold, pressurize and vulcanize to obtain the exhalation valve; wherein, the vulcanization temperature is: 148~154℃, the vulcanization time is 8min, and the vulcanization pressure is 7MPa.

[0024] Example 2 The method is the same as that of Example 1, except that N-methylmorpholine is replaced by tetrahydropyran.

[0025] Example 3 The method is the same as that of Example 1, except that N-methylmorpholine is replaced by dioxane.

[0026] Example 4 The method is the same as that of Example 1, except that the mass ratio of N-methylmorpholine, tetrahydrofuran and naphthalene is 25:50:5.

[0027] Example 5 The method is the same as that of Example 1, except that the thickness of the ETFE film is 50 μm.

[0028] Example 6 The method is the same as that of Example 1, except that the ETFE film material is replaced by the FEP film material.

[0029] Comparative Example 1 The method is the same as that of Example 1, except that the membrane material is not treated with a modifier.

[0030] Comparative Example 2 The method is the same as that of Example 1, except that the membrane material is not subjected to plasma activation and modifier treatment.

[0031] Comparative Example 3 The method is the same as that of Example 1, except that the modifier does not contain N-methylmorpholine, and the mass ratio of tetrahydrofuran to naphthalene is 75:5.

[0032] Comparative Example 4 The method is the same as that of Example 1, except that the film material is not subjected to plasma activation.

[0033] The mechanical strength tests were performed on the above examples and comparative examples, and the results are shown in Table 1.

[0034] Table 1 Comparison of mechanical properties and appearance of coated rubber of Example and Comparative Example

[0035] Low temperature test 1: After the exhalation valve is subjected to a low temperature storage test at -40℃×24h in a low temperature box, it is taken out and tested according to the corresponding test method in GJB1155A-2004, that is, when the exhalation valve is depressurized to -1180Pa, the reverse air tightness value of the exhalation valve is measured within 60s. The reverse air tightness test results are shown in Table 2: Table 2 Reverse air tightness value of exhalation valve within 60s

[0036] GJB 1155A-2004 stipulates that when the exhalation valve is decompressed to -1180Pa, the reverse air tightness of the full-face mask exhalation valve within 60s should not be greater than 350Pa. From the data in Tables 1 and 2, it can be seen that the membrane material treated with a modifier and activated by plasma is more firmly bonded to the natural rubber layer, thus ensuring that the air tightness of the exhalation valve meets the standard.

[0037] Low temperature test 2: Install the exhalation valve on the gas mask, put the installed gas mask into a low temperature box, cool it to (-25±3)℃, and conduct a low temperature working test after stabilization. The low temperature working equipment adopts the equipment in the low temperature protection test method in Article 3.2 of GJB 3662-1999. The exhaled air volume of the electric ventilator is (30±1)L / min, the breathing rate is (22±2) times / min, the exhaled air temperature is (36±1)℃, and the exhaled air humidity is not less than 90%. Observe whether the exhalation valve can open and close freely and whether it fits well with the exhalation valve seat. After working at low temperature for 2h, take it out to check whether there is water vapor icing on the exhalation valve.

[0038] Through experiments, it was found that the exhalation valves prepared in Examples 1 to 6 can be opened and closed when working at low temperatures, move freely, and fit well with the exhalation valve seat. After working at low temperatures for 2 hours, the exhalation valve was taken out for inspection and no ice was formed on it. For Comparative Examples 1 to 4, because there is stratification between the membrane material and the rubber, if there is stratification at the edge of the exhalation valve, there will be a gap at the joint between the exhalation valve and the exhalation valve seat, and it cannot fit well. Its reverse air tightness test will have the problem of being unable to stabilize the pressure when pumping air. Although it can be opened and closed when working at low temperatures, there is a problem of ice forming on the exhalation valve when it is taken out for inspection after working at low temperatures for 2 hours.

[0039] The above results indicate that the exhalation valve prepared in the present application can meet the requirements of using the exhalation valve in a low-temperature environment. When the hot air generated by the human body's rapid breathing comes into contact with the cold external gas after purification, water vapor condensation will not occur on the surface of the exhalation valve due to the temperature difference. This can effectively solve the problem that the exhalation valve of an ordinary gas mask cannot be used due to the easy freezing of the exhaled water vapor.

Claims

1. An exhalation valve for a gas mask suitable for use in a low temperature environment, characterized in that: The invention comprises an exhalation valve body (1) and a hydrophobic layer (2); the exhalation valve body (1) is an umbrella-shaped structure, comprising an exhalation valve umbrella (101) and an exhalation valve umbrella handle (102); the inner side of the exhalation valve umbrella (101) is provided with a hydrophobic layer (2); the hydrophobic layer (2) is one of ETFE or FEP hydrophobic film materials.

2. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 1, characterized in that: The exhalation valve umbrella handle (102) has a groove (3).

3. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 1, characterized in that: The thickness of the exhalation valve umbrella (101) is 0.45-0.5 mm, and the thickness of the hydrophobic layer (2) is 25-75 μm.

4. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 1, characterized in that: The exhalation valve body (1) is made of natural rubber, and the exhalation valve is prepared by vulcanizing a natural rubber compound and a hydrophobic film material; the side of the hydrophobic film material that is in contact with the exhalation valve umbrella (101) is surface treated; the surface treatment method is a modifier treatment and a plasma activation treatment.

5. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 4, characterized in that: The modifier is prepared from sodium, naphthalene and solvent in a mass ratio of 1-3:5-10:75-180; the solvent is a mixture of solvent A and solvent B in a mass ratio of 1:0.5-2; the solvent A is one or more of N-methylmorpholine, tetrahydropyran, 2-methyltetrahydrofuran or dioxane, and the solvent B is tetrahydrofuran.

6. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 4, characterized in that: The plasma activation method is as follows: argon is used as the reaction gas, the gas flow rate is 0.1-0.3 L / min, the discharge voltage is 1.5-4 kV, the frequency is 2-5 kHz, the working distance is 5-8 mm, and the plasma activation layer is formed on the surface of the film material after plasma discharge for 2-6 minutes.

7. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 4, characterized in that: The natural rubber compound has the following proportions: 100 parts of natural rubber, 5-12 parts of zinc oxide, 1-3 parts of stearic acid, 4-8 parts of carbon black, 1-3 parts of vaseline, 8-15 parts of filler, 2-5 parts of antioxidant, 1.2-2.5 parts of accelerator and 0.8-1.5 parts of vulcanizer.

8. The exhalation valve for a gas mask suitable for use in a low temperature environment according to claim 7, characterized in that: The natural rubber is No. 1 smoked sheet rubber.

9. The exhalation valve of a gas mask suitable for use in a low temperature environment according to claim 7, characterized in that: The filler is a sulfate, including one or more of ammonium sulfate, ferric sulfate or sodium sulfate; the antioxidant is a mixed preparation of an amine antioxidant and a wax antioxidant, the weight ratio of the amine antioxidant and the wax antioxidant is 3:2, wherein the amine antioxidant includes any one of antioxidant D, antioxidant RD or antioxidant 4010NA, and the wax antioxidant includes any one of paraffin, ozokerite or microcrystalline wax; the accelerator is a mixed preparation of thiazoles and sulfonamides, the weight ratio of the accelerators is 3:8, wherein the thiazole accelerator includes any one of accelerator DM, accelerator M or accelerator MH; the sulfonamide accelerator includes any one of accelerator CZ, accelerator NOBS or accelerator DZ, and the vulcanizing agent is sulfur.

10. The method for preparing an exhalation valve for a gas mask suitable for use in a low temperature environment according to any one of claims 1 to 9, characterized in that: The following steps are involved: Preparation of the modifier: adding a solvent and naphthalene into a reaction container and stirring to dissolve, then adding sodium and continuing to stir and react to obtain the modifier; Membrane surface treatment: Plasma activation and modifier treatment are performed on one side of the membrane material in sequence to obtain a modified membrane material; Preparation of natural rubber mixed rubber sheet: mixing according to the ratio of 100 parts of natural rubber, 5-12 parts of zinc oxide, 1-3 parts of stearic acid, 4-8 parts of carbon black, 1-3 parts of vaseline, 8-15 parts of filler, 2-5 parts of antioxidant, 1.2-2.5 parts of accelerator and 0.8-1.5 parts of vulcanizing agent to obtain a mixed rubber sheet; Preparation of the exhalation valve: the surface-treated side of the modified membrane material is tightly fitted with the mixed film to obtain a coated film; the coated film is cut to be slightly larger than the exhalation valve mold position by 5-7mm, and when filling, a small piece of uncoated film that is slightly smaller than the exhalation valve umbrella handle by 0.5-1mm is first cut to fill the hole position of the exhalation valve umbrella handle, and then the coated film is spread to the vulcanization area of ​​the exhalation valve to ensure that the coated side is close to the side of the exhalation valve umbrella handle, and then the mold is closed, and pressurized vulcanization is performed to obtain the exhalation valve; wherein, the vulcanization temperature is: 148-154℃, the vulcanization time is 8-10min, and the vulcanization pressure is 7-10MPa.

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