CN112409675A - High-pressure flexible composite pipe material and preparation method thereof - Google Patents

Abstract

The invention discloses a high-pressure flexible composite pipe material and a material for a preparation method thereof, comprising a graft material and a catalytic master batch for cross-linking. The graft material, in parts by weight, includes the following components: 50-95 parts of high-density polyethylene, 5-50 parts of linear low density polyethylene, 0.3-3 parts of modifier, 0.1-1 part of phosphorus-containing antioxidant, 0.2-2 parts of auxiliary antioxidant, 0.003-0.1 part of initiator, 1-3 parts of silane, 0-1 part of adjustment agent; the above-mentioned catalytic master batch, in parts by weight, includes the following components: 80-99 parts of high-density polyethylene, 0.1-1 part of antioxidant, 0.2-1 part of auxiliary antioxidant, dilauric acid two parts 0.02-0.1 part of butyl tin, 0.1-1 part of silicone oil, 0.3-4 part of modifier, 0-1 part of modifier, prepared by preparing materials, configuring mixed pellets, preparing graft materials, configuring catalytic pellets, preparing catalytic master batches and The product is cross-linked to form the Vicat softening point of over 85 degrees after boiling and cross-linking, and the product has a tensile strength of over 28MPA and has good temperature resistance, oil resistance, bending resistance and other properties.

Description

High-pressure flexible composite pipe material and preparation method thereof

Technical Field

The invention relates to a high polymer material, in particular to a high-pressure flexible composite pipe material and a preparation method thereof.

Background

Along with the gradual development of industrial technology, the use amount and the dependency degree of petroleum are gradually improved, so that a large amount of pipe network construction is needed, the existing petroleum pipe network is generally formed by steel skeleton plastic pipes and glass fiber reinforced plastic pipes, through a transportation pipeline which is formed by winding left and right spiral steel wires on a PE core pipe to form a net-shaped framework and fusing the core pipe, a steel wire layer and an externally coated PE layer into a whole by using high-performance modified PE resin, although the pipe has good transportation performance and insufficient temperature resistance, the pipe can only convey media below 40 ℃, and is not suitable for hot melt butt joint during installation, although the glass fiber reinforced plastic pipe has good stability, the glass fiber reinforced plastic pipe has the defects of non-corrosion resistance, poor toughness, easy breakage, short length of a single pipe, more joints, poor temperature adaptability and air tightness and the like in different degrees in the long-term use process, so that the installation and maintenance cost of the petroleum pipeline is obviously increased.

The method for producing crosslinked polyethylene in the prior art mainly comprises chemical crosslinking, radiation crosslinking, silane crosslinking, ultraviolet crosslinking and salt crosslinking, and from the practical production problem, compared with other methods, the silane crosslinking uses less peroxide initiator and is beneficial to keeping high insulation of products, and the silane crosslinking is mainly modified by grafting silane to a polyethylene molecular chain to initiate hydrolysis condensation crosslinking under the action of water and a catalyst. The temperature dimension of the modified polyethylene Vicat obtained by silane crosslinking is improved, but considering that the material temperature in an oil pipe network can cause the risk of thermal expansion of the pipeline, the modified polyethylene still needs a steel framework for distribution, and can not be quickly welded. It is therefore worthwhile to investigate how to optimise composite tube materials.

Disclosure of Invention

The invention aims to provide a high-pressure flexible composite pipe material and a preparation method thereof, aiming at optimizing the problem that the existing crosslinked polyethylene needs a steel framework for distribution on an oil network pipeline when applied, is not easy to be quickly welded, and causes higher construction cost.

In order to solve the technical problems, the invention adopts the following technical scheme:

a high pressure flexible composite tubing material characterized by: the material comprises a grafting material and a catalytic master batch for crosslinking, wherein the grafting material comprises the following components in parts by weight: 50-95 parts of high-density polyethylene, 5-50 parts of linear low-density polyethylene, 0.3-3 parts of modifier, 0.1-1 part of phosphorus-containing antioxidant, 0.2-2 parts of auxiliary antioxidant, 0.003-0.1 part of initiator, 1-3 parts of silane and 0-1 part of regulator; the catalytic master batch comprises the following components in parts by weight: 80-99 parts of high-density polyethylene, 0.1-1 part of antioxidant, 0.2-1 part of auxiliary antioxidant, 0.02-0.1 part of dibutyltin dilaurate, 0.1-1 part of silicone oil, 0.3-4 parts of modifier and 0-1 part of regulator.

Preferably, the grafting material comprises the following components in parts by weight: 55-95 parts of density polyethylene, 5-40 parts of linear low density polyethylene, 0.3-3 parts of modifier, 0.1-0.7 part of phosphorus-containing antioxidant, 0.2-1.3 parts of auxiliary antioxidant, 0.003-0.06 part of initiator, 1.5-3 parts of silane and 0-0.5 part of regulator; the catalytic master batch comprises the following components in parts by weight: 85-99 parts of high-density polyethylene, 0.1-0.5 part of antioxidant, 0.2-0.7 part of auxiliary antioxidant, 0.02-0.1 part of dibutyltin dilaurate, 0.1-0.5 part of silicone oil, 0.3-3 parts of modifier and 0-0.5 part of regulator.

Preferably, the grafting material comprises the following components in parts by weight: 60-95 parts of high-density polyethylene, 5-35 parts of linear low-density polyethylene, 0.3-2 parts of modifier, 0.1-0.5 part of phosphorus-containing antioxidant, 0.2-1 part of auxiliary antioxidant, 0.003-0.01 part of initiator, 1.5-2.5 parts of silane and 0-0.1 part of regulator; the catalytic master batch comprises the following components in parts by weight: 90-99 parts of high-density polyethylene, 0.1-0.5 part of antioxidant, 0.2-0.6 part of auxiliary antioxidant, 0.02-0.08 part of dibutyltin dilaurate, 0.1-0.5 part of silicone oil, 0.3-2 parts of modifier and 0-0.1 part of regulator.

Preferably, the antioxidant is antioxidant 1010, the modifier comprises a silicon-containing modifier and a fluorine-containing modifier, and the initiator is a mixture of DHBP and DCP.

Preferably, the secondary antioxidant is a phosphite antioxidant.

Preferably, the auxiliary antioxidant is dilauryl thiodipropionate.

The invention also discloses a preparation method of the high-pressure flexible composite pipe material, which comprises the following steps,

step A, preparing materials, namely selecting high-density polyethylene and linear low-density polyethylene for preparing materials, mixing the high-density polyethylene and the linear low-density polyethylene, and filtering impurities through a magnetic frame; obtaining a mixture; selecting silane, and pre-melting and screening silane ingredients to obtain silane liquid;

step B, preparing mixed granules, adding an initiator into silane liquid, stirring to obtain a mixed solution, adding a phosphorus-containing antioxidant into the mixed solution, mixing the phosphorus-containing antioxidant into the mixed solution, uniformly stirring to obtain mixed granules, and then adding a modifier into the mixed granules, and uniformly stirring to obtain the mixed granules;

step C, preparing a grafting material, adding the mixed granules, the auxiliary antioxidant and the regulator into a screw extruder for extrusion granulation to obtain grafted granules;

step D, preparing a catalytic particle material, adding an antioxidant into the high-density polyethylene, uniformly stirring, and adding dibutyltin dilaurate for uniform stirring to obtain the catalytic particle material;

e, preparing a catalytic master batch, namely adding the catalytic granular material, silicone oil, a modifier, an auxiliary antioxidant and a regulator into a screw extruder together for extrusion granulation to obtain the catalytic master batch;

and F, product crosslinking, namely uniformly mixing the grafted granules and the catalyst granules, adding the mixture into a screw extruder for extrusion, and putting the extruded sample strip into a constant-temperature water bath kettle for crosslinking.

The further technical scheme is that the temperature range of the constant-temperature water bath is 80-95 ℃, and the crosslinking time in the constant-temperature water bath is 12 hours.

The further technical scheme is that in the process of preparing the grafting material, the temperature of a screw extruder is 270 ℃ at 200-.

Compared with the prior art, the invention has the beneficial effects of at least one of the following:

the pipe material produced by the energy-saving material is detected by a B50 method, the Vicat softening point of the pipe material after water boiling and crosslinking reaches more than 85 degrees, the tensile strength of the product is more than 28MPA, and the elongation at break can reach more than 380%. The injection molding material has good temperature resistance, oil resistance, bending resistance and other properties; thereby being applicable to common oil and gas pipelines.

The composite pipe material provided by the invention can be subjected to quick hot melting butt joint, the installation convenience is improved, and meanwhile, the distribution network efficiency is effectively improved.

The preparation method of the high-pressure flexible composite pipe material provided by the invention can effectively control the stability of the crosslinking reaction, and particularly can take out samples in multiple steps for labeling in the process of testing a high polymer material so as to test various properties.

Detailed Description

In order to make the objects, technical solutions and advantages of the present invention more apparent, the present invention is further described in detail below with reference to the following parameters and examples. It should be understood that the specific embodiments described herein are merely illustrative of the invention and are not intended to limit the invention.

Example 1:

according to one embodiment of the invention, the high-pressure flexible composite pipe material comprises a grafting material and a catalytic master batch which are crosslinked, wherein the crosslinking mode is water boiling crosslinking.

The grafting material comprises the following components in parts by weight: 75 g of high-density polyethylene, 50 g of linear low-density polyethylene, 3 g of modifier, 1 g of phosphorus-containing antioxidant, 2 g of auxiliary antioxidant, 0.1 g of initiator, 3 g of silane and 1 g of regulator.

Wherein, the high-density polyethylene is a raw material sold in the market, and the melt flow rate MFR =0.9g/10min is specifically selected, namely the extruded quantity of the fluid in 10 minutes is 0.9g, so as to ensure good material processing fluidity; and the melt flow index MI =7.0g/10min, wherein the linear low density polyethylene has higher softening temperature and melting temperature compared with the low density polyethylene.

The silane is mainly used for crosslinking high-density polyethylene and linear low-density polyethylene, wherein the phosphorus-containing antioxidant can improve and decompose hydroperoxide, and the silane crosslinked polyethylene has the action principle that the free radical of an initiator acts on the peroxide, so that the vinyl group of the silane is grafted with the polymer, and the polymer containing the trioxysilicone group is further generated; the silicon ester group of the trioxysilicone ester group generates silanol group after hydrolysis, and generates crosslinking action through the polycondensation reaction of the silanol group.

For the graft, the amount of initiator directly affects the quality of the graft, i.e., the gel fraction. When the using amount of the initiator is reduced, the gel fraction of the graft material is obviously reduced, so that the crosslinking performance of the material is influenced, and if the using amount of the initiator is not more than 0.1 g, the grafting content is increased when the content of the initiator is larger, so that the gel fraction is effectively increased.

It should be noted that, in the above formulation, if the amount of the initiator is too large, for example, the amount of the initiator exceeds 0.1 g, the imbalance of the grafting content is promoted, which may cause the number of functional groups contained in the macromolecular chain of the polyethylene to increase sharply during crosslinking, the movement of the macromolecular chain segment is hindered, and the functional groups collide with each other, thereby reducing the chance of crosslinking reaction and further reducing the gel fraction.

The catalytic master batch comprises the following components in parts by weight: 80-99 parts of high-density polyethylene, 0.1-1 part of antioxidant, 0.2-1 part of auxiliary antioxidant, 0.02-0.1 part of dibutyltin dilaurate, 0.1-1 part of silicone oil, 0.3-4 parts of modifier and 0-1 part of regulator.

The dibutyltin dilaurate is used as an existing DBTL raw material, dibutyltin dilaurate is used as a catalytic system, attention needs to be paid to the fact that the dibutyltin dilaurate is used for catalysis, the crosslinking time is mainly influenced, the crosslinking degree and the gel rate are not influenced, and the risk of poor melt flowability and large surface roughness caused by pre-crosslinking of polyethylene components of grafting materials and catalytic master batches during molding can be effectively avoided through the components of the dibutyltin dilaurate in the extrusion molding process of the catalytic master batches and the grafting materials.

As the dibutyltin dilaurate is easy to generate the phenomenon of premature crosslinking and even coking in the catalysis process, the further processing and the performance of a crosslinked product are influenced, the lubricating property in the crosslinking process is realized through the silicone oil component, the uneven distribution of materials in the reaction process is avoided, and the pre-reaction risk in the continuous feeding process is reduced.

The regulator is a compatilizer, and the regulator mainly enables the process of fusing the high-density polyethylene and the linear low-density polyethylene to be better adapted, so that the problem that the crosslinking degree of a product obtained after the two kinds of polyethylene with different densities are grafted and mixed with the catalytic master batch and extruded is not uniform is avoided, and therefore, when the detection is carried out by a B50 method, Vicat fluctuation occurs. Resulting in improved vicat bias.

In the process of cooking and crosslinking, the catalytic master batch and the grafting material are heated and melted into fluid, mixed and stirred by a spiral extruding machine, and then extruded and molded after being mixed by the spiral extruding machine, and the molded product is put into hot water with the temperature of about 90 ℃ for heat preservation and soaking to complete the crosslinking reaction.

Example 2:

based on the above embodiment, another embodiment of the present invention is that the grafting material comprises the following components in parts by weight, 10 g each: 95 parts of density polyethylene, 40 parts of linear low density polyethylene, 3 parts of modifier, 0.7 part of phosphorus-containing antioxidant, 1.3 parts of auxiliary antioxidant, 0.06 part of initiator, 3 parts of silane and 0-part of regulator; the catalytic master batch comprises the following components in parts by weight, 10 g in each part: 99 parts of high-density polyethylene, 0.5 part of antioxidant, 0.7 part of auxiliary antioxidant, 0.1 part of dibutyltin dilaurate, 0.5 part of silicone oil, 3 parts of modifier and 0 part of regulator.

Compared with the common active polyvinyl silane material, the grafting material formed by mixing the high-density polyethylene and the low-density polyethylene has better steric hindrance effect of silicon functional groups in silane molecules, and is beneficial to improving the activity of grafting reaction.

Meanwhile, in the modification process, the free radicals of the silane grafted polyethylene macromolecules influence the branching rate of the grafted macromolecules, the rate of the crosslinking reaction is related to the hydrolytic condensation reaction capability of the alkoxy, and the grafting rate influences the crosslinking degree.

Preferably, the content thereof is 10 g per portion. The grafting material is prepared according to 85 parts of density polyethylene, 35 parts of linear low density polyethylene, 2 parts of modifier, 0.5 part of phosphorus-containing antioxidant, 1 part of auxiliary antioxidant, 0.06 part of initiator, 2 parts of silane and 0.5 part of regulator; the preparation of the catalytic master batch is carried out according to 95 parts of high-density polyethylene, 0.5 part of antioxidant, 0.5 part of auxiliary antioxidant, 0.1 part of dibutyltin dilaurate, 0.5 part of silicone oil, 2 parts of modifier and 0.5 part of regulator.

The regulator is mainly an agent for improving granulation, and is an aid for promoting incompatible two polymers to be combined into a whole by virtue of intermolecular bonding force so as to obtain a stable blend, and in the application process of the grafting material, the regulator is used for enabling high-density polyethylene and low-density polyethylene to form a good blended material in the extrusion molding process, so that the problem that the crosslinking degree of a product obtained after the two polyethylenes with different densities are grafted and mixed with a catalytic master batch for extrusion is not uniform is solved.

The modifier of the grafting material can be maleic anhydride grafting, and the maleic anhydride grafting compatilizer is matched with a reactive group generated by an antioxidant, so that the material has good polarity and reactivity, the compatibility of the material and the dispersibility of raw materials are improved, and for a finally generated product, the tensile strength and the impact strength of the product can be improved, the processing fluidity is improved, and the surface smoothness of a blend is improved.

The regulator of the catalytic master batch can be the existing compatilizer so as to achieve the mixing efficiency among the components.

Example 3:

based on the above embodiments, the difference between the present embodiment and the above embodiments is that the grafting material comprises the following components in parts by weight, per 100 g: 95 parts of high-density polyethylene, 35 parts of linear low-density polyethylene, 2 parts of modifier, 0.5 part of phosphorus-containing antioxidant, 1 part of auxiliary antioxidant, 0.01 part of initiator, 2.5 parts of silane and 0.1 part of regulator; the catalytic master batch comprises the following components in parts by weight, wherein each 100 g of the catalytic master batch comprises the following components: 99 parts of high-density polyethylene, 0.5 part of antioxidant, 0.6 part of auxiliary antioxidant, 0.08 part of dibutyltin dilaurate, 0.5 part of silicone oil, 2 parts of modifier and 0.1 part of regulator.

Further, the antioxidant is antioxidant 1010, wherein the antioxidant is used for slowing down the aging process of the product so as to ensure the stability in the polyethylene processing process and the service life of the product, and the antioxidant absorbs partial free radicals, so that the gel content is influenced; before grafting, polyethylene free radicals can be excessively captured by the antioxidant, so that the silane grafting reaction can be inhibited, and therefore the antioxidant 1010 is more stable.

The oil net pipeline needs to have certain flame retardant resistance in the application process, and the raw materials have good flame retardant effect through the modifier in the prior art. However, the oil net pipeline mainly aimed at by the product is mainly made of polyethylene in raw materials, the organic flame retardant used by the polyethylene can release toxic gas, corrosive gas and smoke during combustion, meanwhile, the flame retardant property of the flame retardant is increased along with the increase of the addition amount, but the mechanical property of the material is greatly reduced due to the addition amount of the flame retardant. For oil pipes, not only the requirement of flame retardance but also good resistance is required, and the stability of the mechanical properties of the material is also ensured. Therefore, the modifier is a silicon-containing modifier and a fluorine-containing modifier,

the fluorine-containing modifier can improve the flame retardance of polyethylene generally, but the flame retardance effect of the fluorine-containing modifier on polyethylene materials is poor. The silicon-containing modifier can be used as a halogen-free flame retardant to neutralize the fluorine-containing modifier, and the flame retardant formed by combining the halogen-free flame retardant and the fluorine-containing modifier can improve the flame retardance and the smoke suppression effect of the material, and meanwhile, the silicon resin and the silicon rubber contained in the silicon-containing modifier and the fluorine-containing modifier can improve the molten drop resistance of the polymer.

The initiator is a mixture of DHBP and DCP. Wherein, the DCP is the existing dicumyl peroxide, and the decomposition temperature and half-life period of the DCP can meet the melting requirement of the polyethylene resin and the organic silicon monomer; the half-life of the dicumyl peroxide at 200 ℃ is 15 seconds, which is consistent with the free radical initiation of silane crosslinking. By introducing the mixed form of DHBP and DCP, a certain free radical concentration is kept in a system for initiating a grafting reaction in unit time, so that the grafting effect is improved, and early curing is avoided.

It should be noted that the DCP is used alone in a range of dosage, and if the dosage of DCP is large, the gel content is rather reduced, so that the fluidity of polyethylene is reduced, and the processability of the graft material is reduced.

In order to ensure that the silane monomer is grafted to polyethylene molecules efficiently and reduce the occurrence of C-C coupling crosslinking, before a large number of molecules are subjected to homolytic cracking, DCP is effectively dispersed into a polymer melt, and the DCP and the silane monomer are ensured to coexist at a certain point of the polyethylene.

Further, the auxiliary antioxidant is a phosphite antioxidant. In the two-step production process, the antioxidant is independently used to influence the grafting rate, in order to eliminate the influence of the antioxidant on the grafting rate, the antioxidant needs to be assisted after the grafting reaction is finished, the grafting and crosslinking degrees can be gradually reduced through the increase of the content of phosphite antioxidant, and when the grafting and crosslinking degrees reach a certain degree, the influence of the antioxidant 1010 on the grafting rate can be controlled.

Furthermore, the auxiliary antioxidant is dilauryl thiodipropionate, because the dilauryl thiodipropionate is produced by using a two-step process, the dilauryl thiodipropionate has the effect of decomposing hydroperoxide and has the effects of no pollution and no coloring when being used as the auxiliary antioxidant, and has a synergistic effect when being used with the antioxidant 1010 and has the auxiliary effect of a certain stabilizer in the crosslinking process.

Example 4:

in one embodiment of the present invention, a method for preparing a high-pressure flexible composite tube material includes the following steps:

step A, preparing materials, namely selecting high-density polyethylene and linear low-density polyethylene for preparing materials, mixing the high-density polyethylene and the linear low-density polyethylene, and filtering impurities through a magnetic frame; obtaining a mixture; selecting silane, and pre-melting and screening silane ingredients to obtain silane liquid;

step B, preparing mixed granules, adding an initiator into silane liquid, stirring to obtain a mixed solution, adding a phosphorus-containing antioxidant into the mixed solution, mixing the phosphorus-containing antioxidant into the mixed solution, uniformly stirring to obtain mixed granules, and then adding a modifier into the mixed granules, and uniformly stirring to obtain the mixed granules;

step C, preparing a grafting material, adding the mixed granules, the auxiliary antioxidant and the regulator into a screw extruder for extrusion granulation to obtain grafted granules;

step D, preparing a catalytic particle material, adding an antioxidant into the high-density polyethylene, uniformly stirring, and adding dibutyltin dilaurate for uniform stirring to obtain the catalytic particle material;

e, preparing a catalytic master batch, namely adding the catalytic granular material, silicone oil, a modifier, an auxiliary antioxidant and a regulator into a screw extruder together for extrusion granulation to obtain the catalytic master batch;

and F, product crosslinking, namely uniformly mixing the grafted granules and the catalyst granules, adding the mixture into a screw extruder for extrusion, and putting the extruded sample strip into a constant-temperature water bath kettle for crosslinking.

Further, the temperature range of the constant-temperature water bath is 80-95 ℃, and the crosslinking time in the constant-temperature water bath is 12 hours.

Further, in the process of preparing the grafting material, the temperature of the screw extruder is 270 ℃ and the rotating speed of the screw is 320 ℃ and 340r/min, in the process of preparing the catalytic master batch, the temperature of the screw extruder is 200 ℃ and the rotating speed of the screw is 180 ℃ and 300r/min, and in the process of crosslinking the product, the temperature of the screw extruder is 300 ℃ and the rotating speed of the screw is 250 r/min.

It should be noted that, in the extrusion process of the silane crosslinked polyethylene, the silane absorbs moisture in the air and is hydrolyzed in advance to generate silanol, the silanol is easy to dehydrate and condense to form a gel condensation polymer under the action of a catalyst, the silane pre-crosslinking phenomenon causes the molecular weight of the silane polyethylene to be increased, and the silane polyethylene is difficult to extrude, so that the production efficiency is affected, and therefore, the moisture of various additives needs to be strictly controlled.

Example 5:

this example prepares the examples for the product parameter; the product is measured by the method B50, namely VST measurement is carried out according to the standard GB/T1633 by using 50N force; the detection instrument is a VST tester which is made of low-expansion alloy so as to ensure the measurement accuracy. The cited standard needs to meet the standard environment of GB/T2918-1998 plastic sample state regulation and test, and the preparation of GB/T9352-1988 thermoplastic plastic compression molding samples; the operation steps before detection are as follows:

step1, detecting a pressure needle head of the VST tester before detection, and determining that the lower surface of the pressure needle head is flat and vertical to the axis of the load rod and has no burrs;

step2, checking whether the dial indicator is corrected, at least meeting the requirement of measuring the penetration degree of the needle pressing head penetrating into the sample by 1mm +/-0.01 mm, and recording the thrust of the dial indicator as a part of the thrust borne by the sample.

Step3, check the load plate, mount on load bar, add appropriate weights in the center, make the total thrust applied to the sample, as determined by the B50 measurement, at least 50N (. + -. 1N). The downward thrust of the load rod, the needle pressing head and the load plate dial indicator spring combination is not more than 1N.

Step4, checking the heating bath, containing the liquid in which the sample is immersed, and arranging a high-efficiency stirrer, wherein the immersion depth of the sample is at least 35 mm; the selected liquid was determined to be stable at the use temperature without affecting the tested material, such as swelling or cracking.

Step5, check the heating equipment, heating bath with liquid or nitrogen circulation oven with forced air. The heating equipment is provided with a controller which can uniformly heat at 50 ℃ per hour (+ -5 ℃) according to requirements. During the test, the heating rate was considered satisfactory at 5 degrees celsius (± 0.5 degrees celsius) every 6 minutes.

Step6, examine the oven, and allow air or nitrogen to circulate through the oven at a rate of 60 times/min. The volume of each oven is not less than 10L, and air or nitrogen in the oven flows perpendicular to the surface of the sample at the speed of 1.5-2 m/s.

Example 6:

the embodiment is a product parameter detection embodiment: taking a product sample with a cross section which can be circular, square or rectangular, wherein the diameter or diagonal length of the product is 10mm, and the thickness of the sample is 3-6.5 mm; the surface of the sample is flat and parallel and has no flash; to meet the GB/T9352, GB/T17037.1 or GB/T11997 moulding sample specifications.

In order to ensure the measurement accuracy, the product is isotropic, but the detection is anisotropic, and when cutting samples, three samples are cut in the same direction at will, and 9 samples are obtained in total.

If the thickness of the sample exceeds 6.5mm, the thickness of the sample is reduced to 3-6.5 mm by single-sided machining according to ISO-2818, and the other surface is kept as it is. It should be noted that the test surface should be the original surface.

If the thickness of the sample is less than 3mm, directly stacking at most three samples together, so that the total thickness of the samples is 3-6.5 mm, and the thickness of the upper piece is at least 1.5 mm. The same test results are not necessarily obtained with sheets of smaller thickness superimposed.

In the detection process, the following steps are strictly carried out:

step.a, the sample is placed horizontally under an unloaded plunger. The distance between the pressure needle head and the edge of the sample is not less than 3mm, and the surface of the sample contacted with the base of the instrument is smooth.

Step.b, the assembly is placed in a heating device, the stirrer is started, and the temperature of the heating device should be 20-23 ℃ at the beginning of each test.

Step.c, when using a heating bath, the mercury bulb of the thermometer or the sensing component of the thermometric instrument should be at the same level as the sample and as close to the sample as possible. It should be noted that other starting temperatures greater than 80 degrees celsius may be used if earlier experiments indicate that the material under test does not cause errors at temperatures greater than 80 degrees celsius.

Step. d, which completes Step3 after 5min of heating bath, the plunger was in the resting position and sufficient weight was added to the load plate to provide a total thrust on the sample, since the B50 method was used, the total thrust was 50N and the tolerance force was ± 1N. The instrument is then zeroed or a dial gauge reading is recorded.

Step.e, raising the temperature of the heating device at a constant speed of 50 degrees celsius per hour (+ -5 degrees celsius); when a heating bath is used, the liquid is stirred well during the test.

And Step F, recording the oil bath temperature measured by the sensor when the pressing needle head penetrates into the sample to a depth of more than 1mm +/-0.01 mm of the initial position specified by Step4, namely the Vicat softening temperature of the sample.

It is noted that the vicat softening temperature of the test material is expressed as the arithmetic mean of the vicat softening temperatures of the test samples. The three directional patterns are independently tested, and if the test results for each directional sample deviate by more than 2 degrees celsius, a single test result is recorded and the test is repeated with another set of at least two remaining samples.

Measuring the linear expansion coefficient of the product according to a GB/T1036-89 plastic linear expansion coefficient measuring method, and mainly detecting the ratio of the length change value of the sample to the original length value of the sample when the temperature of the product changes by 1 ℃. Determining the linear expansion characteristic of the product in a certain temperature interval; the section of the sample is flat and free of burrs, the sample with the original length measured is placed in a quartz dilatometer perpendicular to the long axis, then the sample is inserted into constant temperature baths with different temperatures at minus 30 ℃ or 30 ℃ in sequence, after the temperature is balanced and the dial indicator indicates stability, the reading is recorded, and the average linear expansion coefficient is calculated according to the expansion coefficient value and the contraction coefficient value of the sample. Meanwhile, the heat conductivity coefficient of the product can be measured according to the GB/T3399-1982 plastic heat conductivity coefficient experiment method.

Reference throughout this specification to "one embodiment," "another embodiment," "an embodiment," "a preferred embodiment," or the like, means that a particular feature, structure, or characteristic described in connection with the embodiment is included in at least one embodiment described generally in this application. The appearances of the same phrase in various places in the specification are not necessarily all referring to the same embodiment. Further, when a particular feature, structure, or characteristic is described in connection with any embodiment, it is submitted that it is within the scope of the invention to effect such feature, structure, or characteristic in connection with other embodiments.

Although the invention has been described herein with reference to a number of illustrative embodiments thereof, it should be understood that numerous other modifications and embodiments can be devised by those skilled in the art that will fall within the spirit and scope of the principles of this disclosure. More specifically, various variations and modifications are possible in the component parts and/or arrangements of the subject combination arrangement within the scope of the disclosure, parameters and claims of the present application. In addition to variations and modifications in the component parts and/or arrangements, other uses will also be apparent to those skilled in the art.

Claims (9)

1. A high pressure flexible composite tubing material characterized by: the material comprises a grafting material and a catalytic master batch, is used for crosslinking the composite pipe material, is used for the situation that the Vicat dimension difference exceeds the standard when the composite pipe material with the Vicat temperature lower than 80 ℃ and the composite pipe material with the Vicat temperature higher than 80 ℃ is measured by a B50 method, and is modified and adjusted under the condition of the original base material;

the grafting material comprises the following components in parts by weight: 50-95 parts of high-density polyethylene, 5-50 parts of linear low-density polyethylene, 0.3-3 parts of modifier, 0.1-1 part of phosphorus-containing antioxidant, 0.2-2 parts of auxiliary antioxidant, 0.003-0.1 part of initiator, 1-3 parts of silane and 0-1 part of regulator;

the catalytic master batch comprises the following components in parts by weight: 80-99 parts of high-density polyethylene, 0.1-1 part of antioxidant, 0.2-1 part of auxiliary antioxidant, 0.02-0.1 part of dibutyltin dilaurate, 0.1-1 part of silicone oil, 0.3-4 parts of modifier and 0-1 part of regulator.

2. A high pressure flexible composite tube material according to claim 1, wherein: the grafting material comprises the following components in parts by weight: 55-95 parts of density polyethylene, 5-40 parts of linear low density polyethylene, 0.3-3 parts of modifier, 0.1-0.7 part of phosphorus-containing antioxidant, 0.2-1.3 parts of auxiliary antioxidant, 0.003-0.06 part of initiator, 1.5-3 parts of silane and 0-0.5 part of regulator;

the catalytic master batch comprises the following components in parts by weight: 85-99 parts of high-density polyethylene, 0.1-0.5 part of antioxidant, 0.2-0.7 part of auxiliary antioxidant, 0.02-0.1 part of dibutyltin dilaurate, 0.1-0.5 part of silicone oil, 0.3-3 parts of modifier and 0-0.5 part of regulator.

3. A high pressure flexible composite tube material according to claim 1, wherein: the grafting material comprises the following components in parts by weight: 60-95 parts of high-density polyethylene, 5-35 parts of linear low-density polyethylene, 0.3-2 parts of modifier, 0.1-0.5 part of phosphorus-containing antioxidant, 0.2-1 part of auxiliary antioxidant, 0.003-0.01 part of initiator, 1.5-2.5 parts of silane and 0-0.1 part of regulator;

the catalytic master batch comprises the following components in parts by weight: 90-99 parts of high-density polyethylene, 0.1-0.5 part of antioxidant, 0.2-0.6 part of auxiliary antioxidant, 0.02-0.08 part of dibutyltin dilaurate, 0.1-0.5 part of silicone oil, 0.3-2 parts of modifier and 0-0.1 part of regulator.

4. A high pressure flexible composite tube material according to claim 1, wherein: the antioxidant is an antioxidant 1010, the modifier is a silicon-containing modifier and a fluorine-containing modifier, and the initiator is a mixture of DHBP and DCP.

5. A high pressure flexible composite tube material according to claim 1, wherein: the auxiliary antioxidant is phosphite antioxidant.

6. A high pressure flexible composite tube material according to claim 1, wherein: the auxiliary antioxidant is dilauryl thiodipropionate.

7. A method of manufacturing a high pressure flexible composite tube material, the method of manufacturing a high pressure flexible composite tube material according to any one of claims 1 to 6, comprising the steps of:

step A, preparing materials, namely selecting high-density polyethylene and linear low-density polyethylene for preparing materials, mixing the high-density polyethylene and the linear low-density polyethylene, and filtering impurities through a magnetic frame; obtaining a mixture; selecting silane, and pre-melting and screening silane ingredients to obtain silane liquid;

step B, preparing mixed granules, adding an initiator into silane liquid, stirring to obtain a mixed solution, adding a phosphorus-containing antioxidant into the mixed solution, mixing the phosphorus-containing antioxidant into the mixed solution, uniformly stirring to obtain mixed granules, and then adding a modifier into the mixed granules, and uniformly stirring to obtain the mixed granules;

step C, preparing a grafting material, adding the mixed granules, the auxiliary antioxidant and the regulator into a screw extruder for extrusion granulation to obtain grafted granules;

step D, preparing a catalytic particle material, adding an antioxidant into the high-density polyethylene, uniformly stirring, and adding dibutyltin dilaurate for uniform stirring to obtain the catalytic particle material;

e, preparing a catalytic master batch, namely adding the catalytic granular material, silicone oil, a modifier, an auxiliary antioxidant and a regulator into a screw extruder together for extrusion granulation to obtain the catalytic master batch;

and F, product crosslinking, namely uniformly mixing the grafted granules and the catalyst granules, adding the mixture into a screw extruder for extrusion, and putting the extruded sample strip into a constant-temperature water bath kettle for crosslinking.

8. The method for preparing a high pressure flexible composite tube material according to claim 7, wherein: the temperature range of the constant-temperature water bath is 80-95 ℃, and the crosslinking time in the constant-temperature water bath is 12 hours.

9. The method of making a high pressure flexible composite tubing material of claim 7, wherein: in the process of preparing the grafting material, the temperature of a screw extruder is 270 ℃ at 200-.