CN102677471A - Method for preparing temperature regulation textile by sol-gel technology - Google Patents

Abstract

The invention discloses a method for preparing temperature-regulating fabrics by sol-gel technology. The method for preparing temperature-adjusting fabrics by the sol-gel technology is as follows: adding tetraethyl orthosilicate to a mixed solution of ethanol and water to prepare a tetraethyl orthosilicate solution, and adjusting the pH value to 2-4; Add paraffin, water and emulsifier into the high-speed emulsifier respectively to prepare paraffin core emulsion; slowly add tetraethyl orthosilicate liquid into the paraffin core emulsion, then add synthetic latex to prepare phase change microcapsules Finishing solution: the phase-change microcapsule finishing solution is applied to the fabric by two dipping and two rolling methods, and after being baked, the temperature-adjusting fabric is made. The present invention adopts the sol-gel method, uses tetraethyl orthosilicate as the wall material, and paraffin as the core material phase-change microcolloid finishing solution to prepare the temperature-regulating fabric, which solves the shortcomings of polymers such as urea-formaldehyde resin as the wall material, It improves thermal conductivity, physical and chemical stability, and has good non-toxic and harmless excellent performance.

Description

A method for preparing temperature-adjusting fabrics by sol-gel technology

technical field

The invention belongs to the technical field of chemical industry, and in particular relates to a method for preparing temperature-regulating fabrics by sol-gel technology.

Background technique

Solid-liquid phase change materials have small volume changes and large heat enthalpy during the phase change process, so there are relatively many studies on them in various fields, and their applications are relatively extensive. However, solid-liquid phase change materials are unstable in the phase transition process, which limits their applications. In order to solve this problem, microencapsulation technology is often used to coat the phase change material in the wall material, thereby restricting the flow of the liquid phase change material. Microcapsules usually refer to tiny particles with a diameter between 1-1000 microns. With the development of technology, the diameter of capsules can also reach the nanometer level. Since the capsule is nano-micro, the microcapsule not only solves the leakage problem of the solid-liquid phase change material, but also provides a large heat transfer area, which effectively improves the heat transfer efficiency. At the same time, it prevents the contact of the phase change material with other substances, prevents the change of the properties of the material, and increases the utilization times of the phase change material. Research on microcapsule technology began in the 1950s. In 1954, it was invented by B.KGreen of the National Cash Register Corporation (NCR) and used to produce carbonless copy paper, thus creating an era of new microcapsule technology. In the 1980s, the National Aeronautics and Space Administration (NASA) applied microencapsulated phase change materials to thermal regulation protective clothing and to protect space precision instruments from high temperature interference in space. So far, microencapsulated phase change materials have become the focus of researchers all over the world. hotspot. In the 1990s, Triangle Corporation of the United States synthesized microcapsules with heat absorption and release functions, and finished them on the surface of fabrics to obtain textiles with temperature regulation functions. At present, phase change microcapsules have been widely used in many fields such as textiles, construction, and industrial waste heat recovery.

At present, phase-change microcapsules are mostly coated by in-situ polymerization or interfacial polymerization. For example, Liu Xing, Wang Shujun, etc. use melamine urea-formaldehyde resin as the wall material and paraffin as the core material to prepare phase-change temperature-adjusting microcapsules by in-situ polymerization. . Lai Maobai, Sun Rong, etc. used paraffin as the core material and methyl methacrylate as the wall material, and prepared phase-change microcapsules by interfacial polymerization. The monomer range of the in situ polymerization method is very wide, but the monomer is required to be soluble, while the polymer is insoluble. The interfacial polymerization method does not have strict requirements on the proportion of raw materials, the reaction rate is fast, the effect is good, it can be carried out at room temperature, and the temperature control is simple. However, the monomers used must have high activity for polycondensation reaction. In addition, in-situ polymerization and interfacial polymerization are used to produce phase-change microcapsules, and the walls of the capsules are mostly high polymers, such as urea-formaldehyde resins, copolymers of melamine and formaldehyde, etc., such copolymers are flammable, and such wall materials It has certain harm to the human body, increases potential safety hazards, and is not conducive to the application of textile fabrics. In addition, this type of copolymer makes the prepared phase change microcapsules stick to each other, and has low thermal conductivity, which limits the temperature regulation effect of the phase change material. Based on the above status quo, people began to study other preparation methods of phase change microcapsules and adopt more environmentally friendly and high-performance materials as the wall materials of phase change materials.

Contents of the invention

The purpose of the present invention is to provide a method for coating phase-change microcapsules with sol-gel, so that the phase-change microcapsules have excellent thermal conductivity and better chemical stability.

In order to achieve the above object, the invention provides a method for preparing a temperature-regulating fabric by sol-gel technology, which is characterized in that it comprises the following steps:

Step 1: Weigh 5-15 parts of paraffin, 5-15 parts of tetraethyl orthosilicate, 20-30 parts of emulsifier, 10-20 parts of synthetic latex, 10-20 parts of ethanol and water in parts by mass. 50-70 copies, ready to use;

The second step: under the condition of mechanical stirring, add 5-15 parts of tetraethyl orthosilicate to the mixture of 10-20 parts of ethanol and 10-20 parts of water to prepare a solution of tetraethyl orthosilicate, pH Adjust the value to 2-4;

The third step: respectively add 5-15 parts of paraffin, the remaining water and 20-30 parts of emulsifier into the high-speed emulsifier to prepare a paraffin core emulsion;

The fourth step: under the condition of 55-60°C and mechanical stirring, slowly add the tetraethyl orthosilicate solution obtained in the second step to the paraffin core emulsion obtained in the third step, then add synthetic latex and stir , formulated into a phase-change microcapsule finishing solution;

Step 5: Put the phase-change microcapsule finishing solution obtained in Step 4 on the fabric by two-dipping and two-rolling method to make a temperature-adjusted fabric, the pressure is 2-3kg/cm ² , and the liquid-carrying rate is 60-70% ;

The sixth step: drying the temperature-adjusted fabric prepared in the fifth step at 70-80° C., and then baking at 100-180° C. for 3-5 minutes.

Preferably, the emulsifier in the first step is nonionic fatty alcohol polyoxyethylene ether or nonionic fatty alcohol polyoxyethylene ether propylene ether.

Preferably, the synthetic latex in the first step is acrylic latex or polyurethane aqueous emulsion.

Preferably, the parameters of the mechanical stirring in the second step are: the rotation speed is 300-500 rpm, and the stirring time is 2-4 hours.

Preferably, the rotating speed of the high-speed emulsifying machine in the third step is 10,000 rpm, and the emulsifying time is 20-30 minutes.

Preferably, the stirring speed in the fourth step is 300-500 rpm, and the stirring time is 2 hours.

The present invention adopts the sol-gel method, uses tetraethyl orthosilicate (TEOS) as the wall material, and paraffin is the phase-change microcolloid finishing solution of the core material, and the temperature-adjusting fabric prepared solves the problem that polymers such as urea-formaldehyde resin are used as the wall material. It improves the thermal conductivity, physical and chemical stability, and has good non-toxic and harmless excellent performance. The invention has the advantages of simple technological process, easy control of conditions, low production cost and wide applicability; the raw materials adopted are low in price and wide in sources, and can be applied industrially.

Description of drawings

Fig. 1 is the heat-up performance test diagram of the temperature-regulating fabric prepared by the present invention before and after the external environment temperature changes;

Fig. 2 is a test chart of the cooling performance of the temperature-regulating fabric prepared by the present invention before and after the external environment temperature changes.

Detailed ways

The present invention will be described in detail below in conjunction with the examples.

The paraffin in Examples 1-4 was purchased from Shanghai Huayong Paraffin Co., Ltd.; tetraethyl orthosilicate was purchased from China Pharmaceutical Group Shanghai Chemical Reagent Co., Ltd.; the emulsifier was fatty alcohol polyoxyethylene ether, which was purchased from BASF China Co., Ltd. Company; synthetic latex adopts acrylic latex, which was purchased from BASF China Co., Ltd.

Example 1

Step 1: Dissolve 7g of tetraethyl orthosilicate in a mixture of 14.3g of ethanol and 15g of water under mechanical stirring at 400 rpm, adjust the pH value to 2.6 with hydrochloric acid, and stir for 3 hours to form a stable and uniform Ethyl orthosilicate liquid preparation;

Step 2: Add 6g of paraffin, 37.8g of water and 13g of emulsifier into a high-speed emulsifier, and emulsify for 30 minutes at 10,000 rpm to form a stable and uniform paraffin core emulsion;

Step 3: Under mechanical stirring at 60°C and 400 rpm, slowly add the tetraethyl orthosilicate solution obtained in the first step to the paraffin core emulsion obtained in the second step, and then add 10g of acrylic latex , prepared into a phase-change microcapsule finishing liquid, and stirred evenly for 2 hours.

Example 2

Step 1: Dissolve 5g of tetraethyl orthosilicate in a mixture of 11g of ethanol and 11g of water under mechanical stirring at 400 rpm, adjust the pH value to 2.6 with hydrochloric acid, and stir for 3 hours to form a stable and uniform Ethyl silicate liquid preparation;

Step 2: Add 5g of paraffin, 29g of water and 10g of emulsifier into a high-speed emulsifier, and emulsify for 30 minutes at 10,000 rpm to form a stable and uniform paraffin core emulsion;

Step 3: Under mechanical stirring at 60°C and 400 rpm, slowly add the tetraethyl orthosilicate solution obtained in the first step to the paraffin core emulsion obtained in the second step, and then add 8g of acrylic latex , prepared into a phase-change microcapsule finishing liquid, and stirred evenly for 2 hours.

Example 3

Step 1: Dissolve 10g of tetraethyl orthosilicate in a mixture of 26g of ethanol and 24g of water under mechanical stirring at 400 rpm, adjust the pH to 3.1 with hydrochloric acid, and stir for 3 hours to form a stable and uniform Ethyl silicate liquid preparation;

Step 2: Add 13g of paraffin, 68g of water and 24g of emulsifier into a high-speed emulsifier, and emulsify for 30 minutes at 10,000 rpm to form a stable and uniform paraffin core emulsion;

Step 3: Under mechanical stirring at 60°C and 400 rpm, slowly add the tetraethyl orthosilicate solution obtained in the first step to the paraffin core emulsion obtained in the second step, and then add 19g of acrylic latex , prepared into a phase-change microcapsule finishing liquid, and stirred evenly for 2 hours.

Example 4

The phase-change microcapsule finishing solutions prepared in Examples 1-3 were respectively arranged on plain weave cotton cloth (140g/m ² in grammage) by two-dipping and two-rolling methods to make temperature-regulating fabrics, and the pressure was 3kg/cm ^2. The liquid-carrying rate is 70%; then, dry it in a blast oven at 70°C, and finally bake it at 150°C for 3 minutes.

The original fabric and the above-mentioned temperature-adjusting fabric were respectively tested for their thermal insulation performance according to GB/T 11048-1989. Using the SFJJ-606PC fabric thermal insulation tester, the thermal insulation rate, heat transfer coefficient and Crow value. The test results list is as follows:

Table 1 Fabric thermal insulation performance test before and after finishing

It can be seen from Table 1 that the thermal insulation of the temperature-adjusting fabric is significantly improved compared with the original fabric. With the increase of the content of microcapsules in the preparation solution, the thermal insulation rate of the fabric also increased obviously, and the Cro value also increased correspondingly, and the heat transfer coefficient decreased with the increase of the content of microcapsules in the preparation solution.

Test the temperature rise/fall performance of the original fabric and the above-mentioned temperature-adjusting fabric before and after the external environment temperature changes, the test method is as follows:

1. Temperature rise and fall performance test: put the original fabric and the above temperature-adjusted fabric in a constant temperature and humidity environment for 24 hours to balance (temperature is 20±2°C, relative humidity 65±3%), and then placed on a 36°C insulation board Above, use an infrared thermometer to measure the temperature on the surface of the fabric, record it every 10s, and draw the temperature rise curve of the fabric.

2. Cooling performance test: Put the original fabric and the above-mentioned temperature-adjusted fabric in an oven at 40°C for 2 hours, then take them out and cool them naturally to room temperature (temperature is 20±2°C, relative humidity is 65±3%). The infrared thermometer measures the temperature of the fabric surface, records it every 10s, and draws the fabric cooling curve.

The heating performance test chart is shown in Figure 1, and the cooling performance test chart is shown in Figure 2. The heating rate and cooling rate of the temperature-adjusted fabric decreased compared with the original fabric, and the degree of decrease increased with the increase of the content of microcapsules in the preparation solution. It can be seen from Figure 1 that the fabric after finishing has played a significant role in buffering the external temperature changes.

Claims (6)

1. the method for a sol-gel technology preparing temperature adjustment fabric is characterized in that, may further comprise the steps:

The first step: take by weighing paraffin 5-15 part, ethyl orthosilicate 5-15 part, emulsifying agent 20-30 part, synthetic latex 10-20 part, ethanol 10-20 part and water 50-70 part respectively in mass fraction, for use;

Second step: under churned mechanically condition, 5-15 part ethyl orthosilicate is joined in the mixed liquor of 10-20 part ethanol and 10-20 part water, be mixed with ethyl orthosilicate liquid system liquid, the pH value is adjusted to 2-4;

The 3rd step: respectively 5-15 part paraffin, remaining water and 20-30 part emulsifying agent are joined in the high-speed emulsifying machine, be mixed with the paraffin core emulsion;

The 4th step: under 55-60 ℃, churned mechanically condition, the ethyl orthosilicate liquid system liquid that second step was obtained adds synthetic latex after slowly being added drop-wise in the paraffin core emulsion that the 3rd step obtained, and stirring is mixed with the phase-change microcapsule dressing liquid;

The 5th step: the phase-change microcapsule dressing liquid that the 4th step obtained is put in order on the fabric through two two methods of rolling of soaking, processed the temperature adjustment fabric, pressure is 2-3kg/cm ², liquid carrying rate is 60-70%;

The 6th step: the temperature adjustment fabric that the 5th step made is dried down at 70-80 ℃, under 100-180 ℃, baked 3-5 minute again.

2. the method for sol-gel technology preparing temperature adjustment fabric as claimed in claim 1 is characterized in that, the emulsifying agent in the described first step is nonionic fatty alcohols APEO or nonionic fatty alcohols APEO propylene ether.

3. the method for sol-gel technology preparing temperature adjustment fabric as claimed in claim 1 is characterized in that, the synthetic latex in the described first step is acrylic latex or aqueous emulsion of polyurethane.

4. the method for sol-gel technology preparing temperature adjustment fabric as claimed in claim 1 is characterized in that, the churned mechanically parameter in described second step is: rotating speed 300-500 rev/min, and mixing time 2-4 hour.

5. the method for sol-gel technology preparing temperature adjustment fabric as claimed in claim 1 is characterized in that, the rotating speed of the high-speed emulsifying machine in described the 3rd step is 10000 rev/mins, and emulsification times is 20-30 minute.

6. the method for sol-gel technology preparing temperature adjustment fabric as claimed in claim 1 is characterized in that, the mixing speed in described the 4th step is 300-500 rev/min, and mixing time is 2 hours.

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