CN1331936C - Method for preparing high-temperature-rusistance water-expansible rubber - Google Patents

Abstract

The invention relates to a method for preparing rubber with water-swellable function at 25°C to 150°C by chemical synthesis and physical blending. The method is: copolymerize acrylic acid, sodium acrylate, acrylamide, high temperature resistant modified monomer and crosslinking agent in a certain proportion by reverse suspension method to obtain high temperature resistant water absorbent resin powder, and then make high temperature resistant water absorbent resin The powder and rubber are physically blended and vulcanized to obtain high-temperature water-swellable rubber. The characteristics of the method are that the particle size of the water-absorbing resin is small, less than 5 μm; the water-swelling function is applicable to a wide temperature range, and can be used at high temperatures from 25°C to 150°C; the process is simple, the equipment requirements are low, and the expansion ratio is controllable.

Description

A kind of method for preparing high temperature resistant water-swellable rubber

technical field

The invention relates to the field of sealing materials, in particular to a preparation method of high-temperature-resistant water-swellable rubber.

Background technique

Water swelling rubber (Water swelling Rubber, WSR for short) is a new type of functional material, which is made by introducing hydrophilic functional groups or hydrophilic components into the traditional elastic matrix (rubber). Its mechanism of action is: when in contact with water, water molecules will enter the WSR through physical effects such as diffusion, capillary and surface adsorption, and then form a strong affinity with the hydrophilic groups in the rubber. Absorb water, causing the rubber to deform. When the deformation resistance and osmotic pressure difference are balanced, WSR remains relatively stable, achieving the effect of elasticity and water stop. Since its appearance in the late 1970s and early 1980s, WSR has been known for its unique dual water-stop characteristics of elastic sealing water-stop and water-absorbing expansion water-stop. More and more attention has been paid.

The water-swellable rubber prepared by the blending method has good water absorption performance only at lower temperatures. When the temperature is greater than 30 ° C, the water-swellable rubber decreases with the increase of temperature. When the temperature is close to At 70°C, it hardly absorbs water and swells, thus greatly reducing the expansion rate of water-swellable rubber, resulting in that the water-swellable rubber hardly expands at high temperatures, and cannot achieve the effect of water-stopping, so that it is difficult to put it into use. The water-absorbing resin is modified to make it have a stable structure and high water-absorbing performance under high temperature conditions, thereby broadening its application range, such as improving the water-swellable rubber made of it as the main raw material has water-swelling performance under high temperature will be of great significance.

Zhang Yuhong, He Peixin and others studied the temperature effect of CPE/P(AA-AM) water-swellable elastomer. When the temperature is higher than 30°C, the water absorption rate of water-swellable rubber decreases with the increase of temperature. When the temperature is close to 70°C , almost no water swelling.

Contents of the invention

The purpose of the present invention is to solve the shortcomings of the existing water-swellable rubber such as poor temperature resistance, and use a monomer with a special structure as a comonomer to prepare a high-temperature-resistant water-absorbing resin. The raw material is used to prepare rubber with water-swellable properties at high temperatures from 25°C to 150°C. The characteristics of this method are: ①Water-swellable rubber has a wide temperature range, and can be used in the temperature range of 25°C to 150°C; ②The water-absorbent resin is prepared by a simple reverse-phase suspension polymerization method, and then it is physically blended with rubber It can be obtained by compounding. This method has a simple process and low equipment requirements; ③By changing the ratio of water-absorbing resin and rubber, the expansion rate of water absorption can be controlled, so the expansion rate is controllable.

The purpose of the present invention is to adopt the following technical measures to achieve:

Mix acrylic acid, sodium acrylate, acrylamide, high temperature resistant modified monomer and crosslinking agent with a mass ratio of 20-40:30-60:10-50:10-60:0.1-10, with 30-100mL solvent and 0.1 - Add 5 grams of dispersant into the reactor, stir continuously and raise the temperature, add the initiator dropwise for copolymerization reaction, filter, wash and dry with methanol to obtain water-absorbent resin powder with a particle size of less than 5 μm, and then co-polymerize the water-absorbent resin powder and rubber on an open mill Mixing and adding vulcanization compounding agent to vulcanize the rubber with water swelling function in the range of 25°C to 150°C.

The high temperature resistant modified monomers are vinyl acetate, butyl acrylate, octyl acrylate, lauryl acrylate, stearyl acrylate, butyl methacrylate, octyl methacrylate, decamethacrylate Glycol esters, stearyl methacrylate, 2-acrylamido-2-methylpropanesulfonic acid (AMPS), 3-acrylamidopropyltrimethylammonium chloride, methacrylamidopropyl Trimethylammonium chloride, dimethyldiallylammonium chloride, or 2-methacryloyloxyethyl-dimethyldodecylammonium bromide.

The crosslinking agent is ethylene glycol diacrylate, diethylene glycol diacrylate, polyethylene glycol diacrylate, N, N'-methylenebisacrylamide, pentaerythritol diacrylate or divinyl benzene.

Described solvent is toluene, xylene or cyclohexane.

The dispersant is Span-80, Span-60, Span-20, Tween-80, Tween-60, Tween-20 or sodium dodecylbenzenesulfonate.

Described rubber is natural rubber, neoprene rubber, ethylene propylene rubber, nitrile rubber, chlorinated polyethylene, polyurethane rubber, fluorine rubber, silicon rubber, butyl rubber or styrene-butadiene rubber.

The initiator is potassium persulfate or ammonium persulfate.

The invention has the following advantages: (1) the particle size of the high temperature resistant water-absorbing resin is small, less than 5 μm; (2) the water-swellable rubber has a wide temperature range, and can be used at high temperatures from 25°C to 150°C; (3) through simple The reverse-phase suspension polymerization method is used to prepare water-absorbing materials and then physically blend them with rubber to obtain the material. The process is simple and the equipment requirements are low; (4) the water-absorbing expansion ratio can be controlled by changing the ratio of water-absorbing resin and rubber, so The expansion ratio is controllable.

Compared with common water-swellable rubbers, the water-swellable rubber prepared by the present invention has better water-swellability at high temperature (see the table below). Accurately weigh a certain amount of high-temperature-resistant water-swellable rubber and place it in a small autoclave, add 5-20 times of deionized water, seal it, heat the autoclave to 150°C and keep it for 3 days, then quickly lower it to room temperature, and take out the sample. Wipe off the moisture on the surface with filter paper and weigh.

The weight water absorption S _W of water-swellable rubber is calculated according to the following formula:

${\mathrm{<span\; class="notranslate">\; S</span>}}_{\mathrm{<span\; class="notranslate">\; w</span>}}<span\; class="notranslate">\; (</span><span\; class="notranslate">\; \%</span><span\; class="notranslate">\; )</span><span\; class="notranslate">\; =</span>\frac{{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; 2</span>}}<span\; class="notranslate">\; -</span>{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}{{\mathrm{<span\; class="notranslate">\; W</span>}}_{\mathrm{<span\; class="notranslate">\; 1</span>}}}<span\; class="notranslate">\; \&times;</span>\mathrm{<span\; class="notranslate">\; 100</span>}<span\; class="notranslate">\; \%</span>$

In the formula, W ₁ and W ₂ are the weight of the sample before and after water absorption, respectively.

The results of water swelling experiment

Sample type (150℃, processing time: 3day) Water expansion ratio/% Ordinary water-swellable rubber sample of the present invention 50400

Detailed ways

Example 1

Add 2 g of acrylic acid, 4 g of sodium acrylate, 2 g of acrylamide, 2 g of 2-acrylamido-2-methylpropanesulfonic acid, 0.2 g of diethylene glycol diacrylate, 50 ml of toluene, and 1 g of Span-80 In the reactor, the temperature was raised to 75°C under constant stirring, and the initiator potassium persulfate was added dropwise for copolymerization reaction for 3 hours, filtered, washed and dried with methanol to obtain water-absorbent resin powder, and then 100 parts of nitrile rubber, 30 parts of water-absorbent resin powder , 5 parts of zinc oxide, 2 parts of sulfur, 1 part of anti-aging agent, 20 parts of carbon black, and 2.5 parts of accelerator are blended and vulcanized on an open mill to obtain water-swellable rubber in the range of 25°C to 150°C. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 42 grams.

Example 2

2.5 g of acrylic acid, 3 g of sodium acrylate, 3 g of acrylamide, 1.5 g of 3-acrylamidopropyltrimethylammonium chloride (APTAC), 0.1 g of N,N'-methylenebisacrylamide, 50 mL of solvent Add cyclohexane and 1 gram of Span-60 into the reactor, raise the temperature to 60°C under constant stirring, add the initiator potassium persulfate dropwise for 4 hours of copolymerization reaction, filter, wash and dry with methanol to obtain water-absorbent resin powder, and then 100 parts Nitrile rubber, 30 parts of water-absorbing resin powder, 5 parts of zinc oxide, 2 parts of sulfur, 1 part of anti-aging agent, 20 parts of carbon black, 2.5 parts of accelerator are blended on an open mill and vulcanized at 25°C to 150°C Water-swellable rubber within the range. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 43 grams.

Example 3

3 g of acrylic acid, 3.5 g of sodium acrylate, 1.5 g of acrylamide, 2 g of methacrylamidopropyltrimethylammonium chloride (MPTMA), 0.3 g of N,N'-methylenebisacrylamide, 50 mL of solvent Cyclohexane and 1 gram of Span-60 were added to the reactor, and the temperature was raised to 85°C under constant stirring, and the initiator ammonium persulfate was added dropwise for a copolymerization reaction for 4 hours, filtered, washed and dried with methanol to obtain a water-absorbent resin powder, and then 100 parts Neoprene, 30 parts of water-absorbing resin powder, 1 part of stearic acid, 5 parts of zinc oxide, 4 parts of magnesium oxide, 1 part of anti-aging agent, 30 parts of pottery clay are blended on an open mill and vulcanized at 25 ° C to 150 Rubber that can swell with water in the ℃ range. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 39 grams.

Example 4

Mix 3 g of acrylic acid, 3 g of sodium acrylate, 3 g of acrylamide, 1 g of dimethyldiallyl ammonium chloride (DMDAAC), 0.2 g of diethylene glycol diacrylate, 50 mL of solvent cyclohexane, and 1 g of spar Add -60 into the reactor, heat up to 75°C under constant stirring, add the initiator ammonium persulfate dropwise for 4 hours, then filter, wash and dry with methanol to obtain water-absorbent resin powder, then add 100 parts of natural rubber and 30 parts of water-absorbent resin Powder, 2.5 parts of sulfur, 1 part of accelerator, 5 parts of zinc oxide, 2.5 parts of stearic acid, 20 parts of carbon black, 1 part of anti-aging agent are blended on an open mill, and vulcanized in the range of 25 ° C to 150 ° C Water-swellable rubber. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 41 grams.

Example 5

Mix 2.5 g of acrylic acid, 3 g of sodium acrylate, 3.5 g of acrylamide, 1 g of dimethyldiallylammonium chloride (DMDAAC), 0.4 g of diethylene glycol diacrylate, 50 mL of solvent cyclohexane, and 1 g of Span- Add 60 into the reactor, raise the temperature to 75°C under constant stirring, add the initiator ammonium persulfate dropwise and perform copolymerization for 4 hours, filter, wash and dry with methanol to obtain water-absorbent resin powder, then add 100 parts of ethylene-propylene rubber, 30 parts of water-absorbent resin Powder, 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of accelerator, 1.5 parts of sulfur, and 20 parts of carbon black are blended on an open mill and vulcanized so that they can expand with water in the range of 25 ° C to 150 ° C rubber. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 43 grams.

Example 6

2 grams of acrylic acid, 3 grams of sodium acrylate, 3 grams of acrylamide, 2 grams of 2-methacryloyloxyethyl-dimethyl dodecyl ammonium bromide (DMDA), 0.4 grams of pentaerythritol diacrylate, 50 mL of solvent Add cyclohexane and 1 gram of Span-60 into the reactor, raise the temperature to 75°C under constant stirring, add the initiator ammonium peroxodisulfate dropwise for copolymerization reaction for 4 hours, filter, wash and dry with methanol to obtain water-absorbent resin powder, and then add 100 1 part of ethylene-propylene rubber, 30 parts of water-absorbing resin powder, 5 parts of zinc oxide, 1 part of stearic acid, 2 parts of accelerator, 1.5 parts of sulfur, and 20 parts of carbon black were blended and vulcanized at 25 ° C to Rubber that can expand with water in the range of 150°C. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 41 grams.

Example 7

2.5 grams of acrylic acid, 3 grams of sodium acrylate, 2 grams of acrylamide, 2.5 grams of 2-methacryloyloxyethyl-dimethyl dodecyl ammonium bromide (DMDA), 0.3 grams of ethylene glycol diacrylate, Add 50mL of solvent cyclohexane and 1g of Span-60 into the reactor, raise the temperature to 75°C under constant stirring, add the initiator ammonium persulfate dropwise and perform copolymerization for 4 hours, filter, wash and dry with methanol to obtain water-absorbent resin powder, and then 100 parts of chloroprene rubber, 30 parts of water-absorbing resin powder, 1 part of stearic acid, 5 parts of zinc oxide, 4 parts of magnesium oxide, 1 part of anti-aging agent, and 30 parts of pottery clay are blended on an open mill and vulcanized at 25 ° C. Rubber that can swell with water up to 150°C. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 43 grams.

Example 8

Add 2.5 grams of acrylic acid, 3 grams of sodium acrylate, 3.5 grams of acrylamide, 1 gram of stearyl acrylate, 0.4 diethylene glycol diacrylate, 50 mL of solvent cyclohexane and 1 gram of Tween-80 into the reactor, continuously Stir and raise the temperature to 75°C, add the initiator ammonium persulfate dropwise for 4 hours, filter, wash and dry with methanol to obtain water-absorbent resin powder, then add 100 parts of ethylene-propylene rubber, 30 parts of water-absorbent resin powder, and 5 parts of zinc oxide , 1 part of stearic acid, 2 parts of accelerator, 1.5 parts of sulfur, and 20 parts of carbon black are blended and vulcanized on an open mill to obtain water-swellable rubber in the range of 25°C to 150°C. Weigh 8 grams of the water-swellable rubber and 80 grams of deionized water, put them into an autoclave, seal it, heat the autoclave to 150°C and keep it warm for 3 days, then quickly lower it to room temperature, take out the sample, and wipe off the moisture on the surface with filter paper , weighing 43 grams.

Claims (6)

1, a kind of method for preparing high-temperature-rusistance water-expansible rubber, it is characterized in that with mass ratio being vinylformic acid, sodium acrylate, acrylamide, heat resist modification monomer and the linking agent of 20-40: 30-60: 10-50: 10-60: 0.1-10, add in the reactor with solvent and dispersion agent, stir the back of heating up and drip the initiator copolyreaction, refilter, methanol wash dry the water-absorbing resin powder, the blend in mill with rubber and water-absorbing resin powder then, add vulcanizing ingredient vulcanize high-temperature-rusistance water-expansible rubber;

Described heat resist modification monomer is a vinyl-acetic ester, butyl acrylate, Octyl acrylate, vinylformic acid lauryl alcohol ester, vinylformic acid stearyl alcohol ester, butyl methacrylate, Octyl methacrylate, methacrylic acid lauryl alcohol ester, methacrylic acid stearyl alcohol ester, 2-acrylamido-2-methyl propane sulfonic acid, 3-acrylamido oxypropyl trimethyl ammonium chloride, methacryloyl amido oxypropyl trimethyl ammonium chloride, dimethyl diallyl ammonium chloride or 2-methylacryoyloxyethyl-dimethyl dodecyl bromination ammonium;

Described rubber is natural rubber, chloroprene rubber, ethylene-propylene rubber(EPR), paracril, chlorinatedpolyethylene, urethanes, viton, silicon rubber, isoprene-isobutylene rubber or styrene-butadiene rubber(SBR).

2, a kind of method for preparing high-temperature-rusistance water-expansible rubber according to claim 1, it is characterized in that linking agent is ethylene glycol diacrylate, Diethylene Glycol double methacrylate, polyoxyethylene glycol double methacrylate, N, N '-methylene-bisacrylamide, tetramethylolmethane double methacrylate or Vinylstyrene.

3, a kind of method for preparing high-temperature-rusistance water-expansible rubber according to claim 1 is characterized in that solvent is toluene, dimethylbenzene or hexanaphthene.

4, a kind of method for preparing high-temperature-rusistance water-expansible rubber according to claim 1 is characterized in that dispersion agent is span-80, Si Ban-60, Si Ban-20, tween-80, Tween-60, tween 20 or Sodium dodecylbenzene sulfonate.

5, the method for preparing hydro-expansive rubber according to claim 1, the granularity that it is characterized in that the water-absorbing resin powder is less than 5 μ m

6, the method for preparing hydro-expansive rubber according to claim 1 is characterized in that initiator is Potassium Persulphate or ammonium persulphate.