Preparation method of high-temperature-resistant UHMW-PE film

Abstract

The invention relates to the technical field of preparation of UHMW-PE films, in particular to a preparation method of a high-temperature-resistant UHMW-PE film, which comprises the following steps: step 1, adding a high-temperature-resistant aid into raw material powder of UHMW-PE, and fully and uniformly mixing; 2, the powder is poured into a die-casting die; 3, high-temperature and high-pressure sintering; step 4, cooling; 5, turning is conducted; a high-speed centrifugal mixing mode is adopted, so that the high-temperature-resistant additive and the UHMW-PE powder are uniformly mixed, and in the sintering process, due to the fact that the high-temperature-resistant additive is added and the sintering temperature and pressure are correspondingly changed, the high-temperature-resistant UHMW-PE film is obtained, the original due characteristics of the material can be kept, and the high-temperature-resistant UHMW-PE film can be used for preparing the high-temperature-resistant UHMW-PE film. The high-temperature-resistant rubber hose has the advantages of high temperature resistance, such as wear resistance, chemical corrosion resistance, adhesion resistance and the like, can overcome the defect that the high-temperature-resistant rubber hose is not resistant to high temperature, and plays a good role in filling the blank in the application field of the rubber hose industry at the working temperature of 120-150 DEG C.

Description

Technical Field

[0001] The invention relates to the technical field of UHMW-PE film preparation, and in particular to a method for preparing a high-temperature resistant UHMW-PE film. Background Art

[0002] The fields where UHMW-PE film is applied and the working temperature is above 100℃ include high temperature resistant hoses and some transmission belts with high temperature requirements inside automatic dispensing machines. Since UHMW-PE film, that is, ultra-high molecular weight polyethylene film, still belongs to the polyethylene category, its high temperature resistance is still not good enough. It is generally recommended that its working temperature should not exceed 80 degrees Celsius and at most not exceed 95 degrees Celsius. In this case, taking the application of hoses as an example, if hoses with wear resistance, chemical resistance, anti-adhesion and other properties are required, manufacturers will use UHMMW-PE film when the application environment temperature is not higher than 80 degrees after the hoses are sold, and use polytetrafluoroethylene (PTFE) material when the working temperature is higher than 150 degrees. Whether it is film or pipe, between 80 degrees and 150 degrees, no film is used, and the rubber formula is improved to achieve the best use effect.

[0003] UHMW-PE film is not resistant to high temperature. Its characteristic is that it starts to soften when the temperature exceeds 95 degrees, and its physical properties, such as tensile strength and elongation at break, are affected. The tensile strength of ordinary UHMW-PE film at room temperature is about 53MPA, and the elongation at break is about 400%; at a high temperature of about 110 degrees, after 72 hours, its tensile strength drops to 46MPA, and the elongation at break drops to 330%, and the decline ratios are 13% and 17% respectively. The use of polytetrafluoroethylene material as the lining to improve the high temperature resistance of the hose is currently basically limited to PTFE pipes. PTFE film has not been used in China. The disadvantage is that it is not only costly, but also has poor adhesion to rubber. In this case, once polytetrafluoroethylene and Rubber delamination, all the pressure of the medium in the pipe is completely borne by the PTFE pipe, that is, no matter how the rubber layer of the hose is reinforced, it cannot help it to bear the pressure, so the function of the high-pressure pipe does not exist. Therefore, this is the most common problem that the hose factories that currently use PTFE pipes as linings are most troublesome. If the rubber formula is modified to achieve its high temperature resistance, the current bottleneck is: 1) Due to the complexity of the rubber formula (generally there are dozens of additives), if the high temperature resistance is simply improved without considering the balance of other properties, the colloid will change and affect its vulcanization index; 2) The extreme maximum temperature cannot exceed 150 degrees, and it cannot work at such a temperature for a long time, otherwise the rubber will carbonize; 3) The rubber with high temperature resistant formula is expensive and has a limited service life.

[0004] Therefore, in order to solve the above-mentioned problem of high temperature intolerance, a film preparation method can be designed which can not only maintain the original properties of the material but also overcome its high temperature intolerance. Summary of the invention

[0005] In order to overcome the problem that the existing UHMW-PE film is not resistant to high temperatures.

[0006] The technical solution of the present invention is: a method for preparing a high temperature resistant UHMW-PE film, the steps of which are as follows:

[0007] Step 1: Add high temperature resistant additives to the raw material powder of UHMW-PE, and place it in a mixer, set the speed and stirring time of the mixer until the UHMW-PE raw material powder and the high temperature resistant additives are fully mixed;

[0008] Step 2: Clean the die-casting mold to ensure that the inside of the die-casting mold is clean and free of impurities. Pour the evenly mixed powder in step 1 into the die-casting mold, use a scraper or brush to help the powder spread evenly inside the die-casting mold, and then perform compaction. Stop pressurizing after meeting the compaction density requirements to ensure close contact between powder particles.

[0009] Step 3: high temperature and high pressure sintering, put the die casting mold into the sintering furnace, then close the furnace door, ensure the furnace is sealed, set the sintering temperature, time and pressure parameters, start the furnace heating system, gradually heat up to the set temperature, then keep warm, and carry out the sintering process to make the material fully sintered and densified, and then take out the sintered blank after the furnace temperature drops to the target temperature;

[0010] Step 4: The sintered blank is cooled naturally to ensure that its internal mechanism is dense;

[0011] Step 5: Turning: insert the core rod of the turning equipment into the inner diameter of the cylindrical blank through the hydraulic device, and clamp it on the film turning equipment to ensure that there is an interference fit between the blank and the core rod. Set the turning speed, and then start the film turning equipment to produce a roll of film material.

[0012] Preferably, the amount of the high temperature resistant additive is 2-5% of the UHMW-PE raw material powder.

[0013] Preferably, the loading amount of the mixer does not exceed 70% of the rated capacity, the set rotation speed is 400-1200 r / min, and the stirring time is 5-15 min.

[0014] Preferably, the compaction pressure is 5MPa to 80MPa; the compaction density of the powder is required to be 0.95 to 0.98 g / cm 3 .

[0015] Preferably, the sintering temperature is 280°C and the pressure is 100 kg / cm 2 , the sintering time is 20 to 35 minutes.

[0016] Preferably, the heating rate during sintering is 5 to 10° C. / min.

[0017] Preferably, the target temperature is 150° C. or lower.

[0018] Preferably, the turning speed is 3 to 15 m / min; and the thickness of the film is 0.03 mm to 3 mm.

[0019] The beneficial effects of the present invention are as follows: a high-speed centrifugal mixing method is adopted to uniformly mix the high-temperature resistant additive and the UHMW-PE powder; during the sintering process, due to the addition of the high-temperature resistant additive, the sintering temperature and pressure are changed accordingly, thereby obtaining a high-temperature resistant UHMW-PE film, which can not only maintain the original properties of the material, such as wear resistance, chemical corrosion resistance, and adhesion resistance, but also overcome its high-temperature resistance, and plays a good role in filling the gap in the application field of the hose industry with an operating temperature between 120 and 150 degrees. DETAILED DESCRIPTION

[0020] The present invention will be further described below in conjunction with the embodiments.

[0021] Example 1

[0022] The present invention provides an embodiment: a method for preparing a high temperature resistant UHMW-PE film, the steps of which are as follows:

[0023] Step 1: Add high temperature resistant additives to the raw material powder of UHMW-PE, the dosage of high temperature resistant additives is 2% of the raw material powder of UHMW-PE, and put it into the mixer, set the speed and stirring time of the mixer, the loading of the mixer does not exceed 70% of the rated volume, set the speed to 800r / min, and the stirring time to 10min, until the UHMW-PE raw material powder and the high temperature resistant additives are fully mixed;

[0024] Step 2: Clean the die-casting mold to ensure that the inside of the die-casting mold is clean and free of impurities. Pour the evenly mixed powder in step 1 into the die-casting mold, use a scraper or brush to help the powder spread evenly inside the die-casting mold, and then perform compaction. Stop pressurizing after meeting the compaction density requirements to ensure close contact between powder particles. The compaction pressure is 15MPa, and the compaction density requirement of the powder is 0.65g / cm 3 ;

[0025] Step 3: High temperature and high pressure sintering: Place the die casting mold into the sintering furnace, then close the furnace door to ensure that the furnace is sealed, set the sintering temperature to 280°C and the pressure to 100 kg / cm 2 1. The sintering time is 30 minutes. Start the furnace heating system and gradually heat up to the set temperature. The heating rate during sintering is 5°C / min. Then keep the temperature and carry out the sintering process to make the material fully sintered and densified. After the furnace temperature drops below 150°C, take out the sintered blank.

[0026] Step 4: The sintered blank is cooled naturally to ensure that its internal mechanism is dense;

[0027] Step 5: Turning, insert the core rod of the turning equipment into the inner diameter of the cylindrical blank through the hydraulic device, and clamp it on the film turning equipment to ensure that there is an interference fit between the blank and the core rod. Set the turning speed to 10m / min, and then start the film turning equipment to produce a roll of film material with a thickness of 0.5mm.

[0028] Example 2

[0029] The present invention provides an embodiment: a method for preparing a high temperature resistant UHMW-PE film, the steps of which are as follows:

[0030] Step 1: Add high temperature resistant additives to the raw material powder of UHMW-PE, the dosage of high temperature resistant additives is 4% of the raw material powder of UHMW-PE, and put it into the mixer, set the speed and stirring time of the mixer, the loading amount of the mixer does not exceed 70% of the rated volume, set the speed to 1000r / min, and the stirring time to 15min, until the UHMW-PE raw material powder and the high temperature resistant additives are fully mixed;

[0031] Step 2: Clean the die-casting mold to ensure that the inside of the die-casting mold is clean and free of impurities. Pour the evenly mixed powder in step 1 into the die-casting mold, use a scraper or brush to help the powder spread evenly inside the die-casting mold, and then perform compaction. Stop pressurizing after meeting the compaction density requirements to ensure close contact between powder particles. The compaction pressure is 25MPa, and the compaction density requirement of the powder is 0.98g / cm 3 ;

[0032] Step 3: High temperature and high pressure sintering: Place the die casting mold into the sintering furnace, then close the furnace door to ensure that the furnace is sealed, set the sintering temperature to 280°C and the pressure to 100 kg / cm 2 1. The sintering time is 30 minutes. The furnace heating system is started and the temperature is gradually raised to the set temperature. The heating rate during sintering is 8°C / min. Then the temperature is kept and the sintering process is carried out to make the material fully sintered and densified. After the furnace temperature drops below 150°C, the sintered blank is taken out;

[0033] Step 4: The sintered blank is cooled naturally to ensure that its internal mechanism is dense;

[0034] Step 5: Turning: insert the core rod of the turning equipment into the inner diameter of the cylindrical blank through the hydraulic device, and clamp it on the film turning equipment to ensure that there is an interference fit between the blank and the core rod. Set the turning speed to 10m / min, and then start the film turning equipment to produce a roll of film material with a thickness of 0.6mm.

[0035] Example 3

[0036] The present invention provides an embodiment: a method for preparing a high temperature resistant UHMW-PE film, the steps of which are as follows:

[0037] Step 1: Add high temperature resistant additives to the raw material powder of UHMW-PE, the dosage of high temperature resistant additives is 3.5% of the raw material powder of UHMW-PE, and put it into the mixer, set the speed and stirring time of the mixer, the loading amount of the mixer does not exceed 70% of the rated volume, set the speed to 800r / min, and the stirring time to 15min, until the UHMW-PE raw material powder and the high temperature resistant additive are fully mixed;

[0038] Step 2: Clean the die-casting mold to ensure that the inside of the die-casting mold is clean and free of impurities. Pour the evenly mixed powder in step 1 into the die-casting mold, use a scraper or brush to help the powder spread evenly inside the die-casting mold, and then perform compaction. Stop pressurizing after meeting the compaction density requirements to ensure close contact between powder particles. The compaction pressure is 30MPa, and the compaction density requirement of the powder is 0.97g / cm 3 ;

[0039] Step 3: High temperature and high pressure sintering: Place the die casting mold into the sintering furnace, then close the furnace door to ensure that the furnace is sealed, set the sintering temperature to 280°C and the pressure to 100 kg / cm 2 1. The sintering time is 30 minutes. The furnace heating system is started and the temperature is gradually raised to the set temperature. The heating rate during sintering is 7°C / min. Then the temperature is kept and the sintering process is carried out to make the material fully sintered and densified. After the furnace temperature drops below 150°C, the sintered blank is taken out;

[0040] Step 4: The sintered blank is cooled naturally to ensure that its internal mechanism is dense;

[0041] Step 5: Turning: insert the core rod of the turning equipment into the inner diameter of the cylindrical blank through the hydraulic device, and clamp it on the film turning equipment to ensure that there is an interference fit between the blank and the core rod. Set the turning speed to 150m / min, and then start the film turning equipment to produce a roll of film material with a thickness of 0.3mm.

[0042] Table 1 is a table of performance indicators of UHMW-PE films prepared by the methods of Examples 1, 2 and 3 of the present invention.

[0043]

[0044]

[0045] Table 1

[0046] The embodiments of the present invention are described in detail above, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of those skilled in the art without departing from the spirit of the present invention.

Claims

1. A method for preparing a high temperature resistant UHMW-PE film, characterized in that: The steps are as follows: Step 1: Add high temperature resistant additives to the raw material powder of UHMW-PE, and place it in a mixer, set the speed and stirring time of the mixer until the UHMW-PE raw material powder and the high temperature resistant additives are fully mixed; Step 2: Clean the die-casting mold to ensure that the inside of the die-casting mold is clean and free of impurities. Pour the evenly mixed powder in step 1 into the die-casting mold, use a scraper or brush to help the powder spread evenly inside the die-casting mold, and then perform compaction. Stop pressurizing after meeting the compaction density requirements to ensure close contact between powder particles. Step 3: high temperature and high pressure sintering, put the die casting mold into the sintering furnace, then close the furnace door, ensure the furnace is sealed, set the sintering temperature, time and pressure parameters, start the furnace heating system, gradually heat up to the set temperature, then keep warm, and carry out the sintering process to make the material fully sintered and densified, and then take out the sintered blank after the furnace temperature drops to the target temperature; Step 4: The sintered blank is cooled naturally to ensure that its internal mechanism is dense; Step 5: Turning: insert the core rod of the turning equipment into the inner diameter of the cylindrical blank through the hydraulic device, and clamp it on the film turning equipment to ensure that there is an interference fit between the blank and the core rod. Set the turning speed, and then start the film turning equipment to produce a roll of film material.

2. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The dosage of the high temperature resistant additive is 2-5% of the UHMW-PE raw material powder.

3. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The loading amount of the mixer shall not exceed 70% of the rated capacity, the set speed shall be 400-1200r / min, and the stirring time shall be 5-15min.

4. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The compaction pressure is 5MPa~80MPa; the compaction density of the powder is required to be 0.95~0.98g / cm 3 .

5. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The sintering temperature is 280℃ and the pressure is 100㎏ / cm 2 , the sintering time is 20 to 35 minutes.

6. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The heating rate during sintering is 5-10°C / min.

7. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The target temperature is 150°C or less.

8. The method for preparing a high temperature resistant UHMW-PE film according to claim 1, characterized in that: The turning speed is 3 to 15 m / min; the thickness of the film is 0.03 mm to 3 mm.

Images