A kind of polypropylene hot melt adhesive and its preparation method and application

Abstract

The present invention provides a polypropylene hot melt adhesive, comprising: 45-65wt% of terpolymer polypropylene; 15-25wt% of ethylene-acrylate-maleic anhydride copolymer; 5-10wt% of copolymer polyamide; 5-30wt% of ethylene-propylene rubber; antioxidant; the mass of the antioxidant is 0.3-0.5% of the total mass of terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber. The polypropylene hot melt adhesive provided by the present invention is used for polypropylene heat shrinkable tape to improve its high temperature resistance. The heat resistance grade of the polypropylene hot melt adhesive and its heat shrinkable tape for steel oil pipeline provided by the present invention can withstand 130°C. The polypropylene hot melt adhesive provided by the present invention reduces the installation temperature of the polypropylene heat shrinkable tape, which is convenient for construction. The polypropylene heat shrinkable tape provided by the present invention can be installed at 130°C, shortening the heating time and avoiding the risk of carbonization of the epoxy coating. The present invention also provides a preparation method and application of a polypropylene hot melt adhesive.

Description

Technical Field

[0001] The present invention belongs to the technical field of oil and gas pipeline anti-corrosion, and in particular relates to a polypropylene hot melt adhesive and a preparation method and application thereof, specifically a polypropylene hot melt adhesive for oil pipeline weld anti-corrosion and a preparation method thereof, and a method for preparing a polypropylene heat shrink tape using the hot melt adhesive. Background Art

[0002] Three-layer polyethylene (3PE) and three-layer polypropylene (3PP) are common anti-corrosion methods for oil pipelines. The so-called three-layer structure means that the surface of the steel pipe is painted with epoxy primer, and the outer polypropylene substrate and the epoxy coating are firmly bonded by the middle layer of hot melt adhesive to form a three-layer anti-corrosion layer. The design operating temperature of the oil pipeline is different for different conveying media, and the selected anti-corrosion layer is also different. 3PE is selected for pipelines with an operating temperature below 80°C, and 3PP can be selected for pipelines with higher operating temperatures. The 3PP anti-corrosion layer is more common in the Middle East, and the requirements for temperature resistance have risen rapidly from 90°C to 130°C in recent years.

[0003] There is little research on polypropylene hot melt adhesive and heat shrink tape products for oil pipeline corrosion protection in my country. The existing polypropylene hot melt adhesive is only suitable for 100-120℃ and cannot meet the strength requirements of 130℃. The existing polypropylene hot melt adhesive uses maleic anhydride grafted homopolymer polypropylene or two-component copolymer polypropylene, which has high crystallinity and high melting point. It needs to be heated continuously for a long time and can only melt at a relatively high temperature, so the construction time is long. The installation temperature of the existing polypropylene heat shrink tape is high. The epoxy primer layer needs to be heated for a long time before installation, and the risk of overheating and carbonization of the epoxy coating is high.

[0004] The temperature resistance of polypropylene hot melt adhesive and its heat shrink tape in the prior art cannot reach 130℃, and the high melting point makes the construction difficult. GTS-PPII clearly requires that the minimum installation temperature must not be less than 170℃, but long-term baking may cause carbonization of the epoxy coating, affecting the service life of the anti-corrosion layer. Improving the high temperature resistance of polypropylene hot melt adhesive and reducing the installation temperature of polypropylene heat shrink tape are urgent problems to be solved in this field. Summary of the invention

[0005] In view of this, the object of the present invention is to provide a polypropylene hot melt adhesive and a preparation method and application thereof. The polypropylene hot melt adhesive provided by the present invention has an installation temperature lower than 130°C and can be used in a high temperature environment of 130°C.

[0006] The present invention provides a polypropylene hot melt adhesive, comprising:

[0007] 45-65wt% terpolymer polypropylene;

[0008] 15-25wt% of ethylene-acrylate-maleic anhydride copolymer;

[0009] 5-10wt% of copolyamide;

[0010] 5-30wt% ethylene-propylene rubber;

[0011] Antioxidants;

[0012] The weight of the antioxidant is 0.3-0.5% of the total weight of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0013] Preferably, the terpolymer polypropylene is copolymerized from materials including propylene, ethylene and butene-1.

[0014] Preferably, the melting point of the terpolymer polypropylene is 125°C to 140°C.

[0015] Preferably, the mass content of the copolymerized anhydride in the ethylene-acrylate-maleic anhydride copolymer is 2.5% to 4.8%.

[0016] Preferably, the melting point of the ethylene-acrylate-maleic anhydride copolymer is 75-110°C.

[0017] Preferably, the melting point of the copolymerized polyamide is 120-135° C., and the melt index is 20-35 g / 10 min.

[0018] Preferably, the antioxidant is a hindered phenol antioxidant.

[0019] The present invention provides a method for preparing the polypropylene hot melt adhesive described in the above technical solution, comprising:

[0020] Mixing and melting terpolymer polypropylene and ethylene-propylene rubber to obtain a melt;

[0021] kneading the melt and the copolyamide to obtain a mixture;

[0022] The mixture is mixed with ethylene-acrylate-maleic anhydride copolymer and an antioxidant to obtain a polypropylene hot melt adhesive.

[0023] Preferably, the temperature of the mixed melting is 160-165°C and the time is 15-20 minutes;

[0024] The kneading time is 10 to 15 minutes;

[0025] The mixing time is 25 to 30 minutes.

[0026] The present invention provides a polypropylene heat shrinkable tape, which is prepared from a material including the polypropylene hot melt adhesive described in the above technical solution.

[0027] The present invention adopts terpolymer polypropylene as the main provider of high-temperature strength. Compared with high-melting-point homopolymer polypropylene and random or block polypropylene, the terpolymer polypropylene is copolymerized by propylene, ethylene and butene-1. The insertion of ethylene and butene copolymerization destroys the continuous chain structure and crystallization behavior of the propylene molecular chain, and finally forms a mixed polypropylene composed of a low melting point, low crystallinity component and a relatively high melting point, high crystallinity component, so that the terpolymer polypropylene has the advantages of low initial melting temperature, wide melting range and high temperature resistance (the melting point of the terpolymer polypropylene is 125-138°C). Using ethylene-acrylate-maleic anhydride copolymer as the main provider of bonding factors for primer steel can enable polypropylene hot melt adhesive to achieve low-temperature bonding; compared with maleic anhydride grafted polypropylene, it has the characteristics of high bonding activity and low melting point; the anhydride content in the copolymer is 2.5% to 4.8%, while the anhydride grafting rate of ordinary maleic anhydride grafted polypropylene is only 0.6 to 1.2%, and the more polar anhydride functional groups on the long chain of the polymer, the stronger the bonding activity to the hydroxyl groups on the surface of the epoxy coating; maleic anhydride grafted polypropylene uses high-melting point homopolymer or binary copolymer polypropylene as the main body, and the obtained graft has a relatively high melting point, generally >150°C, which also makes the melting point of the finally prepared polypropylene hot melt adhesive remain high, and the present invention uses ethylene-acrylate-maleic anhydride copolymer as the provider of bonding force, and its melting point is 75 to 110°C, which can achieve bonding at low installation temperature. The copolymerized polyamide in the present invention has both a polar amide structure, which can increase the adhesion of the polypropylene hot melt adhesive, and a high fluidity characteristic, which improves the flowability of the hot melt adhesive; the ethylene propylene rubber exhibits rubber viscoelasticity at high temperatures, which can increase the melt strength of the hot melt adhesive and improve the high-temperature peel strength and shear strength.

[0028] The polypropylene hot melt adhesive provided by the present invention is used for the polypropylene heat shrinkable tape to improve its high temperature resistance. The polypropylene hot melt adhesive for steel oil pipeline and the heat shrinkable tape provided by the present invention can withstand a temperature grade of 130°C. The polypropylene hot melt adhesive provided by the present invention reduces the installation temperature of the polypropylene heat shrinkable tape, which is convenient for construction. The polypropylene heat shrinkable tape provided by the present invention can be installed at 130°C, shortening the heating time and avoiding the risk of carbonization of the epoxy coating. DETAILED DESCRIPTION

[0029] The technical solutions in the embodiments of the present invention are described clearly and completely below. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0030] The present invention provides a polypropylene hot melt adhesive, comprising:

[0031] 45-65wt% terpolymer polypropylene;

[0032] 15-25wt% of ethylene-acrylate-maleic anhydride copolymer;

[0033] 5-10wt% of copolyamide;

[0034] 5-30wt% ethylene-propylene rubber;

[0035] Antioxidants;

[0036] The weight of the antioxidant is 0.3-0.5% of the total weight of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0037] In the present invention, the mass content of the terpolymer polypropylene is preferably 50-60%, more preferably 55%.

[0038] In the present invention, the terpolymer polypropylene is preferably copolymerized from materials including propylene, ethylene and butene-1; the melting point is preferably 125°C to 140°C, more preferably 130 to 135°C.

[0039] In the present invention, the terpolymer polypropylene can be purchased from the market, such as FS5612, FS6612 produced by Singapore TPC or F5006 produced by Yanshan Petrochemical.

[0040] In the present invention, the mass content of the ethylene-acrylate-maleic anhydride copolymer is preferably 18-22%, more preferably 20%.

[0041] In the present invention, the mass content of the co-anhydride in the ethylene-acrylate-maleic anhydride copolymer (the mass fraction of MAH on the copolymer) is preferably 2.5% to 4.8%, more preferably 3.0 to 4.5%, and most preferably 3.5 to 4.0%; the melting point is preferably 75 to 110°C, more preferably 80 to 105°C, more preferably 85 to 100°C, and most preferably 90 to 95°C.

[0042] In the present invention, the ethylene-acrylate-maleic anhydride copolymer can be purchased from the market, such as EBA-MAH 4210, 3210, EMA-MAH3430 or EEA-MAH8200 produced by Arkema of France.

[0043] In the present invention, the mass content of the copolymerized polyamide is preferably 6 to 9%, more preferably 7 to 8%.

[0044] In the present invention, the melting point of the copolymerized polyamide is preferably 120-135° C., more preferably 125-130° C.; the melt index is preferably 20-35 g / 10 min, more preferably 25-30 g / 10 min.

[0045] In the present invention, the copolyamide can be purchased from the market, such as copolyamide 201A produced by Nantong Xinxing or M-30 produced by Shanghai Zhenwei.

[0046] In the present invention, the mass content of the ethylene-propylene rubber is preferably 10-25%, more preferably 15-20%.

[0047] In the present invention, the EPDM rubber is preferably in granular form, and the diameter of the EPDM rubber is preferably 3 to 7 mm, more preferably 4 to 6 mm, and most preferably 5 mm.

[0048] In the present invention, the ethylene propylene rubber can be purchased from the market, such as 3080P produced by China National Petroleum Corporation, or 4725P and 4770P produced by Dow Chemical of the United States.

[0049] In the present invention, the weight of the antioxidant is preferably 0.35-0.45% of the total weight of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber, and more preferably 0.4%.

[0050] In the present invention, the antioxidant is preferably a hindered phenol antioxidant 1010.

[0051] The present invention provides a method for preparing the polypropylene hot melt adhesive described in the above technical solution, comprising:

[0052] Mixing and melting terpolymer polypropylene and ethylene-propylene rubber to obtain a melt;

[0053] kneading the melt and the copolyamide to obtain a mixture;

[0054] The mixture is mixed with ethylene-acrylate-maleic anhydride copolymer and an antioxidant to obtain a polypropylene hot melt adhesive.

[0055] In the present invention, the mixed melting is preferably stirred in a twin-rotor kneader; the temperature of the mixed melting is preferably 160-165°C, more preferably 161-164°C, and most preferably 162-163°C; the time of the mixed melting is preferably 15-20 min, more preferably 16-19 min, and most preferably 17-18 min.

[0056] In the present invention, the kneading time is preferably 10 to 15 min, more preferably 11 to 14 min, and most preferably 12 to 13 min.

[0057] In the present invention, the mixing time is preferably 25 to 30 min, more preferably 26 to 29 min, and most preferably 27 to 28 min.

[0058] In the present invention, the preparation method of the polypropylene hot melt adhesive preferably includes:

[0059] The preparation is completed in a twin-rotor kneader, the heating temperature of the kneader is set at 160-165° C. First, 45-65% by weight of terpolymer polypropylene and 5-30% by weight of ethylene-propylene rubber are placed in a twin-rotor kneader at a temperature of 160-165° C. and stirred for 15-20 minutes. After they are melted, 5-10% by weight of copolymer polyamide are added, and kneading is continued for 10-15 minutes. Then, 15-25% by weight of ethylene-acrylate-maleic anhydride copolymer and 0.3-0.5% by weight of antioxidant are added, and kneading is continued for 25-30 minutes. The rubber preparation is completed and ready for use.

[0060] The present invention provides a polypropylene heat shrinkable tape, which is prepared from a material including the polypropylene hot melt adhesive described in the above technical solution.

[0061] The present invention provides a method for preparing the polypropylene heat shrinkable tape described in the above technical solution, comprising:

[0062] The polypropylene hot melt adhesive is calendered and coated on a carrier substrate to obtain a polypropylene heat shrinkable tape.

[0063] In the present invention, the calender coating is preferably carried out at the coating roller of the stretching coating machine. In the present invention, the polypropylene hot melt adhesive is preferably transported to the coating roller of the stretching coating machine through a pipeline with a screw pusher at the end; the temperature of the pipeline is preferably 160-170°C, more preferably 165°C. In the present invention, the substrate is preferably a cross-linked polypropylene substrate that is heat-stretched.

[0064] In the present invention, a polypropylene heat shrinkable tape is prepared on a stretching glue coating machine; the stretching zone is composed of high-temperature rollers with different rotation speeds, and the polypropylene substrate is heated when passing through, part of the crystal zone melts, the substrate becomes soft and elastic, and the stretching force generated by the roller speed difference stretches it radially, so that it has heat shrinkage characteristics; the stretched polypropylene substrate enters the glue coating zone, and the glue coating zone is connected to a kneading machine for preparing polypropylene hot melt adhesive by a glue discharge pipeline, and a screw pushing device is built-in at the end of the glue discharge pipeline close to the kneading machine; the polypropylene hot melt adhesive is sent to the glue coating zone through the glue discharge pipeline, and is combined with the polypropylene substrate by hot pressing to form a polypropylene heat shrinkable tape.

[0065] In the present invention, the stretching glue coating machine preferably includes a heating zone 1, a heating zone 2, a heating zone 3, a glue coating zone and a traction zone; the heating zone 1 preferably includes: a stretching zone 1 and a stretching zone 2; the roller speed of the stretching zone 1 is preferably 2.4 to 2.5 m / min, more preferably 2.42 to 2.46 m / min, and most preferably 2.44 m / min; the roller speed of the stretching zone 2 is preferably 2.48 to 2.52 m / min, more preferably 2.50 m / min; the temperature of the heating zone 1 is preferably 130 to 150°C, more preferably 135~145℃, most preferably 140℃; the heating zone 2 preferably includes: stretching zone 3, stretching zone 4 and stretching zone 5; the roller speed of the stretching zone 3 is preferably 2.48~2.52m / min, more preferably 2.50m / min; the roller speed of the stretching zone 4 is preferably 2.50~2.55m / min, more preferably 2.51~2.54m / min, most preferably 2.53m / min; the stretching zone 5 is preferably 2.54~2.58m / min, more preferably 2.55~2.57m / min n, most preferably 2.56m / min; the temperature of the second heating zone is preferably 140-160°C, more preferably 145-155°C, and most preferably 150°C; the third heating zone preferably includes: a sixth stretching zone and a seventh stretching zone; the roller speed of the sixth stretching zone is preferably 2.58-2.62m / min, more preferably 2.60m / min; the roller speed of the seventh stretching zone is preferably 2.59-2.62m / min, more preferably 2.61m / min; the temperature of the third heating zone is preferably 145-155°C, more preferably 150°C It is 148-152°C, and 150°C is most preferred; the roller speed of the glue coating roller in the glue coating area is preferably 2.59-2.63m / min, more preferably 2.60-2.62m / min, and most preferably 2.61m / min; the temperature of the glue coating roller is preferably 140-145°C, more preferably 141-144°C, and most preferably 142-143°C; the roller speed in the traction zone is preferably 2.57-2.61m / min, more preferably 2.58-2.60m / min, and most preferably 2.59m / min.

[0066] Compared with the existing polypropylene hot melt adhesive with a melting point of 160 to 175°C, the polypropylene hot melt adhesive provided by the present invention has a melting point below 140°C. The low melting point makes it easier to heat and melt, and is convenient to use. The polypropylene hot melt adhesive provided by the present invention has a shear strength of >1.7MPa at 130°C, a peel strength of >2.5N / mm for primer steel, and a shear strength of >2.1MPa at 120°C, and a peel strength of >3.5N / mm for primer steel. It has the characteristics of high strength at high temperatures and can be used in a 130°C environment. Compared with the installation temperature of the existing polypropylene heat shrinkable tape above 170°C, the installation temperature of the polypropylene heat shrinkable tape provided by the present invention is less than or equal to 130°C, which reduces the heating temperature of the epoxy coating and avoids carbonization of the epoxy coating. The polypropylene hot melt adhesive and polypropylene heat shrinkable tape provided by the present invention can be installed at 130°C, and are suitable for patching and corrosion protection of 130°C high-temperature oil pipelines, and have the advantages of high temperature resistance and low installation temperature.

[0067] Example 1

[0068] The polypropylene hot melt adhesive comprises the following components: 48% by weight of terpolymer polypropylene FS6612, 20% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 6% by weight of copolymer polyamide 201A, 26% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0069] Preparation method of polypropylene hot melt adhesive: The heating temperature of the twin-rotor kneader is set to 160-165°C and preheated for 2 hours. Add the terpolymer polypropylene and ethylene-propylene rubber into the kneader and stir for 15-20 minutes. After they are melted (30 minutes), add the copolymer polyamide and continue kneading for 10-15 minutes. Then add the ethylene-acrylate-maleic anhydride copolymer and the antioxidant and continue kneading for 25-30 minutes. The adhesive is ready for use.

[0070] Preparation method of polypropylene heat shrinkable tape: The preparation process of polypropylene heat shrinkable tape is to apply the finished polypropylene hot melt adhesive to the stretched polypropylene substrate. This process needs to be implemented on a stretching glue coating machine; the temperature and roller speed parameters of each zone of the stretching glue coating machine are shown in the following table:

[0071]

[0072] The polypropylene substrate is sequentially wrapped around the stretching rollers in zones one to seven, and the polypropylene substrate is stretched by the stretching force generated by the speed difference of the stretching rollers; then it is introduced into the gluing zone via the transition roller, and the temperature of the gluing roller is set at 140-145°C; the temperature of the glue discharge pipe just above the gluing roller is 150-155°C; the screw pushing device and the glue discharge pipe valve at the end of the kneading machine are started, and the polypropylene hot melt adhesive flows along the glue discharge pipe to the gluing roller, and the gap and speed of the gluing roller are adjusted to thermally press the hot melt adhesive and the polypropylene substrate into one, so as to make a polypropylene heat shrinkable tape.

[0073] The melting point and shear strength of the polypropylene hot melt adhesive prepared in Example 1 were tested; the peel strength of the primer steel was tested for the heat shrinkable tape prepared in Example 1. The installation temperature was measured by a contact thermometer or an infrared thermometer, and the installation process was as follows: sandblasting and rust removal of the steel pipe, heating the steel pipe with a propane spray gun or a medium frequency device, and then applying epoxy coating (two-component solvent-free CP-1 type epoxy primer produced by Jiangsu Baolitai, the main component of component A is phenolic epoxy resin, the main component of component B is amine curing agent, and components AB are mixed before use), heating again after the coating is cured, testing the surface temperature of the coated steel pipe (i.e., installation temperature) with a contact thermometer or an infrared thermometer, wrapping the heat shrinkable tape, heating, and shrinking the heat shrinkable tape tightly around the steel pipe, and continuing to heat until the hot melt adhesive is completely melted.

[0074] The premise for polypropylene hot melt adhesive to achieve bonding is to heat it to melt. Part of the heat for melting comes from the surface of the steel pipe, that is, the installation temperature, and the other part comes from the continuous external heating after the heat shrink tape is wrapped. External heating requires heat to be transferred from the outer layer of the heat shrink tape with a thickness greater than or equal to 1.5 mm to the inner layer of the hot melt adhesive. Polypropylene is a poor conductor of heat. It is extremely difficult to melt the polypropylene hot melt adhesive by gradually transferring heat through external heating. In view of this, the temperature of the steel pipe before wrapping the heat shrink tape is very important, because if the installation temperature of the steel pipe is greater than or closer to the melting point of the polypropylene hot melt adhesive, the polypropylene hot melt adhesive may melt instantly on the surface or be closer to melting as a whole after contacting the steel pipe. The less heat is required for external heating later, and the shorter the heating duration. Considering the above situation and the fact that the thermal conductivity of steel materials is much better than that of polypropylene materials, and that too long a later heating time may cause the polypropylene heat shrink tape to burn and carbonize, it is generally adopted to heat the steel pipe to a higher temperature before wrapping the heat shrink tape to shorten the later heating time. If the temperature of the steel pipe is heated to a temperature higher than the melting point of the polypropylene hot melt adhesive in the early stage, so that the hot melt adhesive melts as soon as it touches the steel pipe, theoretically the subsequent heating can be omitted. However, in actual operation, the performance of the coating on the surface of the steel pipe will be degraded due to excessive heat.

[0075]

[0076] Example 2

[0077] The polypropylene hot melt adhesive comprises the following components: 45% by weight of terpolymer polypropylene FS5612, 15% by weight of ethylene-acrylate-maleic anhydride copolymer 8200, 10% by weight of copolymer polyamide 201A, 30% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0078] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0079] The various performance indicators of the polypropylene hot melt adhesive and its heat shrink tape prepared in Example 2 were tested, and the test results are shown in the following table:

[0080]

[0081] Example 3

[0082] The polypropylene hot melt adhesive comprises the following components: 52% by weight of terpolymer polypropylene FS5612, 23% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 7% by weight of copolymer polyamide M-30, 18% by weight of ethylene-propylene rubber 4725P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.4% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0083] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0084] The various performance indicators of the polypropylene hot melt adhesive and its heat shrink tape prepared in Example 3 were tested, and the test results are shown in the following table:

[0085]

[0086] Example 4

[0087] The polypropylene hot melt adhesive comprises the following components: 55% by weight of terpolymer polypropylene FS6612, 25% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 5% by weight of copolymer polyamide M-30, 15% by weight of ethylene-propylene rubber 4770P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0088] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0089] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 4 were tested, and the test results are shown in the following table:

[0090]

[0091] Example 5

[0092] The polypropylene hot melt adhesive comprises the following components: 57% by weight of terpolymer polypropylene FS6612, 19% by weight of ethylene-acrylate-maleic anhydride copolymer 4210, 8% by weight of copolymer polyamide 201A, 26% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0093] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0094] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 5 were tested, and the test results are shown in the following table:

[0095]

[0096] Example 6

[0097] The polypropylene hot melt adhesive comprises the following components: 46% by weight of terpolymer polypropylene F5006, 17% by weight of ethylene-acrylate-maleic anhydride copolymer 8200, 10% by weight of copolymer polyamide 201A, 27% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.5% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0098] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0099] The various performance indicators of the polypropylene hot melt adhesive and its heat shrink tape prepared in Example 6 were tested, and the test results are shown in the following table:

[0100]

[0101] Example 7

[0102] The polypropylene hot melt adhesive comprises the following components: 60% by weight of terpolymer polypropylene FS5612, 25% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 5% by weight of copolymer polyamide 201A, 10% by weight of ethylene-propylene rubber 4770P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0103] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0104] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 7 were tested, and the test results are shown in the following table:

[0105]

[0106] Example 8

[0107] The polypropylene hot melt adhesive comprises the following components: 63% by weight of ternary copolymer polypropylene F5006, 22% by weight of ethylene-acrylate-maleic anhydride copolymer 4210, 8% by weight of copolymer polyamide 201A, 7% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the ternary copolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0108] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0109] The various performance indicators of the polypropylene hot melt adhesive and its heat shrink tape prepared in Example 8 were tested, and the test results are shown in the following table:

[0110]

[0111] Example 9

[0112] The polypropylene hot melt adhesive comprises the following components: 65% by weight of ternary copolymer polypropylene F5006, 15% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 5% by weight of copolymer polyamide 201A, 15% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the ternary copolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0113] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0114] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 9 were tested, and the test results are shown in the following table:

[0115]

[0116] Example 10

[0117] The polypropylene hot melt adhesive comprises the following components: 60% by weight of terpolymer polypropylene FS5612, 16% by weight of ethylene-acrylate-maleic anhydride copolymer 3210, 13% by weight of copolymer polyamide 201A, 11% by weight of ethylene-propylene rubber 4725P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.5% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0118] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0119] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 10 were tested, and the test results are shown in the following table:

[0120]

[0121] Embodiment 11

[0122] The polypropylene hot melt adhesive comprises the following components: 62% by weight of ternary copolymer polypropylene F5006, 18% by weight of ethylene-acrylate-maleic anhydride copolymer 8200, 9% by weight of copolymer polyamide 201A, 11% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the ternary copolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0123] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0124] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 11 were tested, and the test results are shown in the following table:

[0125]

[0126] Example 12

[0127] The polypropylene hot melt adhesive comprises the following components: 50% by weight of terpolymer polypropylene F5006, 21% by weight of ethylene-acrylate-maleic anhydride copolymer 3430, 7% by weight of copolymer polyamide 201A, 22% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0128] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0129] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 12 were tested, and the test results are shown in the following table:

[0130]

[0131] Example 13

[0132] The polypropylene hot melt adhesive comprises the following components: 58% by weight of terpolymer polypropylene FS6612, 20% by weight of ethylene-acrylate-maleic anhydride copolymer 4210, 10% by weight of copolymer polyamide 201A, 12% by weight of ethylene-propylene rubber 4770P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.3% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0133] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0134] The various performance indicators of the polypropylene hot melt adhesive and the heat shrinkable tape prepared in Example 13 were tested, and the test results are shown in the following table:

[0135]

[0136] Embodiment 14

[0137] The polypropylene hot melt adhesive comprises the following components: 47% by weight of terpolymer polypropylene F5006, 22% by weight of ethylene-acrylate-maleic anhydride copolymer 8200, 10% by weight of copolymer polyamide 201A, 21% by weight of ethylene-propylene rubber 3080P, and antioxidant 1010, wherein the mass of the oxidant 1010 is 0.4% of the total mass of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

[0138] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Example 1.

[0139] The various performance indicators of the polypropylene hot melt adhesive and its heat shrink tape prepared in Example 14 were tested, and the test results are shown in the following table:

[0140]

[0141] Comparative Example 1

[0142] The polypropylene hot melt adhesive includes the following components: 43% by weight of random polypropylene grafted maleic anhydride (grafting rate 0.9%), 15% by weight of block polypropylene grafted maleic anhydride (grafting rate 1.1%), 20% by weight of polyethylene grafted maleic anhydride (grafting rate 1.0%), 22% by weight of Dow POE8450, and antioxidant 1010. The mass of the oxidant 1010 is 0.5% of the total mass of random polypropylene grafted maleic anhydride, block polypropylene grafted maleic anhydride, polyethylene grafted maleic anhydride and Dow POE8450.

[0143] The preparation method is as follows: the above raw materials are mixed evenly and then put into a screw extruder, and the temperature setting of the extruder is shown in the table below to obtain a polypropylene hot melt adhesive; the raw materials are melt-mixed in the extruder (polypropylene hot melt adhesive) and then coated on a polypropylene substrate to obtain a polypropylene heat shrink tape.

[0144] Each district Zone 1 Zone 2 Zone 3 District 4 District 5 District 6 Die head area 1 Die 2 Zone Die head zone 3 Temperature ℃ 100 140 170 190 200 200 210 205 210

[0145] Comparative Example 2

[0146] The polypropylene hot melt adhesive includes the following components: 26% by weight of random polypropylene grafted maleic anhydride (grafting rate 0.9%), 54% by weight of block polypropylene grafted maleic anhydride (grafting rate 1.1%), 20% by weight of Dow POE8450, and antioxidant 1010. The mass of the oxidant 1010 is 0.5% of the total mass of random polypropylene grafted maleic anhydride, block polypropylene grafted maleic anhydride and Dow POE8450.

[0147] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Comparative Example 1.

[0148] Comparative Example 3

[0149] The polypropylene hot melt adhesive includes the following components: 25% by weight of random polypropylene grafted maleic anhydride (grafting rate 0.9%), 32% by weight of block polypropylene grafted maleic anhydride (grafting rate 1.1%), 33% by weight of polyethylene grafted maleic anhydride (grafting rate 1.0%), 10% by weight of Dow POE8450, and antioxidant 1010. The mass of the oxidant 1010 is 0.5% of the total mass of random polypropylene grafted maleic anhydride, block polypropylene grafted maleic anhydride, polyethylene grafted maleic anhydride and Dow POE8450.

[0150] Polypropylene hot melt adhesive and polypropylene heat shrink tape were prepared according to the method of Comparative Example 1.

[0151] The performance indicators of the polypropylene hot melt adhesive and polypropylene heat shrink tape prepared in Comparative Examples 1 to 3 were tested, and the test results are shown in the following table:

[0152]

[0153] In Examples 1 to 14, terpolymer polypropylene is the main provider of low melting point and high temperature shear strength, and plays a role in promoting the bonding of hot melt adhesive and polypropylene; compared with high melting point homopolymer polypropylene and random or block polypropylene, terpolymer polypropylene is formed by copolymerization of propylene, ethylene, and butene-1. The insertion of ethylene and butene copolymerization destroys the continuous chain structure and crystallization behavior of the propylene molecular chain, and finally forms a mixed polypropylene composed of low melting point, low crystallinity components and relatively high melting point, high crystallinity components, so that it has the advantages of low initial melting temperature, wide melting range, and high temperature resistance. Ethylene-acrylate-maleic anhydride copolymer is the main provider of bonding factors for primer steel. The anhydride content is 2.5% to 4.8%, which ensures that the hot melt adhesive has strong bonding activity to the hydroxyl and other groups on the surface of the epoxy coating. The melting point of 75 to 110°C helps to achieve bonding at low installation temperature. Copolymer polyamide has both polar amide structure and high fluidity, which can increase the bonding property of polypropylene hot melt adhesive and improve flowability. Ethylene propylene rubber exhibits rubber viscoelasticity at high temperatures, which can increase the melt strength of hot melt adhesives and improve the temperature resistance level; granular ethylene propylene rubber is easy to add and disperse. Hindered phenol antioxidant 1010 (pentaerythritol tetrakis[β-(3,5-di-tert-butyl-4-hydroxyphenyl) propionate) is a general antioxidant in this field, and its purpose is to inhibit the aging of polypropylene hot melt adhesives during preparation.

[0154] It can be seen from the performance test data of each embodiment that the polypropylene heat shrinkable tape provided by the present invention has the advantages of low installation temperature, high high temperature strength and high temperature resistance. Compared with the existing common polypropylene hot melt adhesive and polypropylene heat shrinkable tape, the installation temperature is reduced from 170°C to below 130°C, which is convenient for construction and application; the shear strength at 130°C can reach 2.0MPa, and the peel strength can reach 3.9N / mm, which can be used in a high temperature environment of 130°C.

[0155] Although the present invention has been described and illustrated with reference to specific embodiments of the present invention, these descriptions and illustrations do not limit the present invention. It will be clearly understood by those skilled in the art that various changes may be made without departing from the true spirit and scope of the present invention as defined by the appended claims, so that specific circumstances, materials, material compositions, materials, methods or processes are suitable for the goals, spirit and scope of the present application. All such modifications are intended to be within the scope of the appended claims. Although the methods disclosed herein have been described with reference to specific operations performed in a specific order, it should be understood that these operations may be combined, subdivided or reordered to form equivalent methods without departing from the teachings of the present invention. Therefore, unless specifically indicated herein, the order and grouping of operations are not limitations of the present application.

Claims

1. A polypropylene hot melt adhesive comprising: 45-65wt% of terpolymer polypropylene; the terpolymer polypropylene is copolymerized from materials including propylene, ethylene and butene-1; the melting point of the terpolymer polypropylene is 125°C-140°C; 15-25wt% of ethylene-acrylate-maleic anhydride copolymer; the mass content of copolymerized anhydride in the ethylene-acrylate-maleic anhydride copolymer is 2.5%-4.8%; the melting point of the ethylene-acrylate-maleic anhydride copolymer is 75-110°C; 5-10wt% of copolyamide; the copolyamide has a melting point of 120-135°C and a melt index of 20-35g / 10min; 5~30wt% EPDM; Antioxidants; The weight of the antioxidant is 0.3-0.5% of the total weight of the terpolymer polypropylene, ethylene-acrylate-maleic anhydride copolymer, copolymer polyamide and ethylene-propylene rubber.

2. The polypropylene hot melt adhesive according to claim 1, characterized in that: The antioxidant is a hindered phenol antioxidant.

3. A method for preparing the polypropylene hot melt adhesive according to claim 1, comprising: Mixing and melting terpolymer polypropylene and ethylene-propylene rubber to obtain a melt; kneading the melt and the copolyamide to obtain a mixture; The mixture is mixed with ethylene-acrylate-maleic anhydride copolymer and an antioxidant to obtain a polypropylene hot melt adhesive.

4. The method according to claim 3, characterized in that: The temperature of the mixed melting is 160-165°C and the time is 15-20 minutes; The kneading time is 10 to 15 minutes; The mixing time is 25 to 30 minutes.

5. A polypropylene heat shrinkable tape, prepared from a material comprising the polypropylene hot melt adhesive according to claim 1.

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