1. The resin material for coating is characterized by comprising the following raw materials in parts by weight:

2. the coating resin material according to claim 1, wherein the antioxidant is at least one of the antioxidants TH-412S, 1010, DSTDP.

3. The coating resin material as claimed in claim 2, wherein the antioxidant is the antioxidant TH-412S, the antioxidant 1010 and the antioxidant DSTDP, which are compounded according to the weight ratio of 3:1: 1.

4. The coating resin material as claimed in claim 1, wherein the light stabilizer is a hindered amine light stabilizer.

5. The coating resin material according to claim 1, wherein the PP resin is a mixture of isotactic homopolyPP and block copolymeric PP.

6. The coating resin material according to claim 5, wherein the weight ratio of the isotactic homopolymer PP to the block copolymer PP is 1:1 to 1: 4.

7. The coating resin material according to claim 6, wherein a weight ratio of the isotactic homopolymer PP to the block copolymer PP is 1: 3.

8. The coating resin material according to claim 1, wherein the titanium dioxide is a nano-sized titanium dioxide having a particle diameter of 10nm to 100 nm.

9. The coating resin material according to claim 1, wherein the silica is a nano-scale silica having a particle size of 10nm to 100 nm.

10. A method for preparing a coating resin material according to any one of claims 1 to 9, comprising the steps of:

s1, weighing the PP resin, the antioxidant, the light stabilizer, the titanium dioxide, the pigment and the silicon dioxide according to the weight part ratio, and fully mixing;

s2, putting the mixed materials into an extruder for melting, extruding and granulating; when the mixed materials enter an extruder, the mixed materials are sequentially melted through a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice, wherein the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa;

s3, putting the granules obtained in the step S2 into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Background

Most of refrigeration functions of the existing refrigeration industry are that a compressor is matched with a refrigerant, heat release and heat absorption are realized through condensation and evaporation of the refrigerant, so that heat exchange is carried out, wherein most of pipelines for transmitting the refrigerant are copper tubes. Firstly, China lacks copper ore and is used as a large import country of copper, and the cost advantage of copper pipes is absolutely not available at the moment of copper price rising; secondly, the heat conductivity of copper is excellent, so that the application of the copper pipe on an evaporator and a condenser has excellent heat exchange effect, but on a refrigerant transmission pipeline, only the heat loss is increased, the heat exchange efficiency is reduced, and the energy consumption is increased; then, the copper pipe is used as a refrigerant transmission pipe, part of the copper pipe is usually exposed in an outdoor environment, and the copper pipe is usually corroded after being used for a long time in outdoor environments with variable environments, particularly in seaside cities, and is actually blackened or verdigris is formed, so that the refrigerant leakage refrigeration is finally caused to be invalid; finally, the copper pipe often has insufficient length in the actual installation process, the copper pipe is usually lengthened by brazing, welding is not suitable for all occasions, and certain environmental pollution is caused by welding.

Aiming at the above conditions, a plurality of uneven copper aluminum pipes are appeared on the market, the two ends of the copper pipes are connected by pure aluminum in the middle through resistance welding, and a PE heat shrinkable sleeve is added at the position of the copper-aluminum welding part and the middle aluminum, the main function of the PE heat shrinkable sleeve is to protect the copper-aluminum welding part and the pure aluminum, so as to prevent electrochemical corrosion and oxidation in a complex natural environment, but the current PE heat shrinkable sleeve is not tightly attached to a pipe body, and the highest temperature capable of bearing by the PE heat shrinkable sleeve is only 100 ℃, so that the use requirements in the industry cannot be met.

Disclosure of Invention

The invention mainly aims to provide an energy-saving and environment-friendly polypropylene resin material which is special for the outside of an aluminum pipe, has super-strong peeling strength, high and low temperature impact resistance, corrosion resistance and light aging resistance, has excellent heat insulation performance, has the peeling strength of 5N/mm (which is not changed after high and low temperature aging), has the highest high temperature resistance of 150 ℃, the low temperature resistance of-40 ℃, does not have any corrosion after 1000h of salt spray test, does not crack after 1000h of ultraviolet irradiation, and has the energy loss reduced by 20 percent compared with a copper pipe.

In order to achieve the above object, the present application provides a resin material for coating, comprising the following raw materials in parts by weight: 100 parts of PP resin, 0.1-0.5 part of antioxidant, 0.1-0.5 part of light stabilizer, 0.1-1.0 part of titanium dioxide, 0.1-3.0 parts of pigment and 0.1-6.0 parts of silicon dioxide.

As a further improvement of the application, the antioxidant is at least one of antioxidant TH-412S, antioxidant 1010 and antioxidant DSTDP.

As a further improvement of the application, the antioxidant is prepared by compounding an antioxidant TH-412S, an antioxidant 1010 and an antioxidant DSTDP according to the weight ratio of 3:1: 1.

As a further improvement herein, the light stabilizer is a hindered amine light stabilizer.

As a further improvement herein, the PP resin is a mixture of isotactic homopolypp and block copolymeric PP.

As a further improvement of the application, the weight ratio of the isotactic homopolymer PP to the block copolymer PP is 1: 1-1: 4.

As a further improvement of the present application, the weight ratio of the isotactic homopolyPP to the block copolymeric PP is 1: 3.

As a further improvement of the application, the titanium dioxide is nano-scale titanium dioxide, and the particle size of the nano-scale titanium dioxide is 10 nm-100 nm.

As a further improvement of the application, the silicon dioxide is nanoscale silicon dioxide, and the particle size of the nanoscale silicon dioxide is 10 nm-100 nm.

In order to achieve the above object, the present application provides a method for preparing the above coating resin material, comprising the steps of: s1, weighing the PP resin, the antioxidant, the light stabilizer, the titanium dioxide, the pigment and the silicon dioxide according to the weight part ratio, and fully mixing; s2, putting the mixed materials into an extruder for melting, extruding and granulating; when the mixed materials enter an extruder, the mixed materials are sequentially melted through a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice, wherein the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; s3, putting the granules obtained in the step S2 into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

The resin material for coating has the beneficial effects that the PP resin is used as a main material, the tensile strength, the bending strength and the impact strength of the PP are increased by adding the titanium dioxide, and in addition, the titanium dioxide is stable in chemical property, non-toxic, good in heat resistance, capable of shielding ultraviolet light of all bands and capable of enhancing the anti-aging and anti-ultraviolet performances; by adding the silicon dioxide, the melting point of the PP resin is improved, and the hardness and the heat resistance of the surface of the material are improved while the thermal deformation temperature is increased; by adding the antioxidant, the heat resistance and oxidation resistance of the material are obviously improved, and the fundamental problem that the material cannot be used for a long time at high temperature is solved; by adding hindered amine light stabilizer, the photooxidation resistance and weather resistance of the material are improved; the preparation process of the PP resin material provided by the invention is simple, no additional equipment is required to be added, and the cost is low.

Detailed Description

In order to make the objects, technical solutions and advantages of the present application more apparent, the technical solutions of the present application will be described in detail and completely with reference to the specific embodiments of the present application. It should be understood that the described embodiments are only a few embodiments of the present application, not all embodiments, and are not intended to limit the scope of the present invention. All other embodiments, which can be derived by a person skilled in the art from the embodiments given herein without making any creative effort, shall fall within the protection scope of the present application.

The application provides a resin material for coating, which mainly comprises PP resin. In order to prepare the resin material for coating the refrigerant pipe for external use having suitability for a specific environment, in some embodiments, the PP resin is preferably a mixture of isotactic homopolymer PP and block copolymer PP. Preferably, the block copolymer PP is prepared by introducing 10% of ethylene monomer after propylene polymerization for block copolymerization. Further preferably, the weight ratio of the isotactic homopolymer PP to the block copolymer PP is 1:1 to 1: 4. More preferably, the weight ratio of the isotactic homopolyPP to the block copolymeric PP is 1: 3.

In the resin material for coating provided by the application, an antioxidant is also added into the PP resin. The antioxidant can prevent thermal oxidation degradation in the processing process of some polymers, so that the molding processing of the polymers can be smoothly carried out. In order to satisfy the application scenarios of the refrigerant transmission pipeline in the present application, especially the copper-aluminum welding part and the middle aluminum part in the pipeline, the antioxidant may be, but is not limited to, at least one of antioxidant TH-412S, antioxidant 1010, and antioxidant DSTDP. Preferably, the antioxidant is an antioxidant TH-412S. More preferably, the antioxidant can also be preferably a compound antioxidant, and specifically, the compound antioxidant is prepared by compounding an antioxidant TH-412S, an antioxidant 1010 and an antioxidant DSTDP according to the weight part ratio of 3:1: 1. In the application, the addition amount of the antioxidant can be 0.1 to 0.5 parts by weight based on 100 parts by weight of the PP resin raw material. Preferably, the antioxidant may be added in an amount of 0.3 to 0.5 parts by weight, and in an embodiment of the present invention, the antioxidant may be added in an amount of 0.1, 0.3, or 0.5 parts by weight.

In the application, a light stabilizer is further added into the PP resin, and the light stabilizer can be, but not limited to, a hindered amine light stabilizer, and the hindered amine light stabilizer has high-efficiency light stabilizing performance. In the present application, the amount of the light stabilizer added may be 0.1 to 0.5 parts by weight based on 100 parts by weight of the PP resin raw material. Preferably, the light stabilizer may be added in an amount of 0.3 to 0.5 parts by weight. Specifically, in the embodiment of the present invention, the antioxidant may be added in an amount of 0.1 part, 0.3 part, or 0.5 part by weight.

In the application, titanium dioxide is added into the PP resin, so that the tensile strength, the bending strength and the impact strength of the PP resin are improved, and the ageing resistance and the ultraviolet resistance of the PP resin are enhanced. The type of titanium dioxide may be, but is not limited to, rutile titanium dioxide. Preferably, the titanium dioxide is nanoscale titanium dioxide. More preferably, the particle size of the nano-scale titanium dioxide is 10nm to 100 nm. More preferably, the nano-sized titanium dioxide preferably has a particle size of 20nm to 50 nm. In the present application, the titanium dioxide may be added in an amount of 0.1 to 1.0 part by weight based on 100 parts by weight of the PP resin raw material. Preferably, the titanium dioxide may be added in an amount of 0.3 to 0.8 parts by weight. Specifically, in the embodiment of the present invention, the titanium dioxide may be added in an amount of 0.1 part, or 0.3 part, or 0.8 part by weight.

In the application, silicon dioxide is added into the PP resin, so that the ageing resistance of the PP resin material is improved, the melting point of the PP resin is also improved by adding the silicon dioxide, and the hardness and the heat resistance of the surface of the material are also improved while the thermal deformation temperature is increased. Preferably, the silica is nanoscale silica. More preferably, the particle size of the nano-scale silica is 10nm to 100 nm. More preferably, the particle size of the nano-sized silica is more preferably 20nm to 35 nm. In the present application, the amount of the silica added may be 0.1 to 1.0 part by weight based on 100 parts by weight of the PP resin raw material. Preferably, the silica may be added in an amount of 0.5 to 0.8 parts by weight. Specifically, in the embodiment of the present invention, the amount of the silica added may be 0.1 part, or 0.5 part, or 0.8 part by weight.

In the present application, pigments are further added to the PP resin in order to impart various colors suitable for viewing and appreciation to the coating resin material. In the present application, the pigment may be, but is not limited to, iron sesquioxide. In the present application, the pigment may be added in an amount of 0.1 to 3.0 parts by weight based on 100 parts by weight of the PP resin raw material. Preferably, the pigment may be added in an amount of 0.3 to 0.5 parts by weight. Specifically in embodiments of the present invention, the pigment may be 0.3 parts or 0.5 parts.

To further illustrate the technical solution disclosed in the present invention, the following is illustrated by 1 to 9 embodiments and 1 to 2 comparative examples:

example 1

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.1 part of antioxidant TH-412S, 0.1 part of hindered amine light stabilizer, 0.1 part of titanium dioxide, 0.1 part of nano silicon dioxide and 0.3 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 2

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.3 part of antioxidant TH-412S, 0.3 part of hindered amine light stabilizer, 0.1 part of titanium dioxide, 0.1 part of nano silicon dioxide and 0.3 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 3

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.5 part of antioxidant TH-412S, 0.5 part of hindered amine light stabilizer, 0.5 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 4

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.3 part of antioxidant TH-412S, 0.3 part of hindered amine light stabilizer, 0.3 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 5

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.5 part of antioxidant TH-412S, 0.5 part of hindered amine light stabilizer, 0.8 part of titanium dioxide, 0.8 part of nano silicon dioxide and 0.3 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 6

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 10100.5 parts of antioxidant, 0.5 part of hindered amine light stabilizer, 0.5 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 7

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.5 part of antioxidant DSTDP, 0.5 part of hindered amine light stabilizer, 0.5 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 8

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.5 part of antioxidant, 0.5 part of hindered amine light stabilizer, 0.5 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and the components are fully mixed, wherein: the weight part ratio of the antioxidant 1010 to the antioxidant DSTDP is 1: 1; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Example 9

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:3), 0.5 part of antioxidant, 0.5 part of hindered amine light stabilizer, 0.5 part of titanium dioxide, 0.5 part of nano silicon dioxide and 0.5 part of ferric oxide, and the components are fully mixed, wherein: the weight part ratio of the antioxidant TH-412S, the antioxidant 1010 and the antioxidant DSTDP in the antioxidant is 3:1: 1; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Comparative example 1

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:1), 0.1 part of antioxidant TH-412S, 0.1 part of hindered amine light stabilizer, 0.1 part of titanium dioxide, 0.1 part of nano silicon dioxide and 0.3 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

Comparative example 2

Weighing the following raw materials in parts by weight: 100 parts of PP resin (isotactic homopolymerization: block copolymerization is 1:4), 0.1 part of antioxidant TH-412S, 0.1 part of hindered amine light stabilizer, 0.1 part of titanium dioxide, 0.1 part of nano silicon dioxide and 0.3 part of ferric oxide, and fully mixing; the mixed materials are put into an extruder for melting, extruding and granulating, wherein when the mixed materials enter the extruder, the mixed materials are respectively melted by a first section of machine barrel section, a second section of machine barrel section, a third section of machine barrel section and an extrusion die orifice in sequence, the temperature of the first section of machine barrel section is 170-190 ℃, the temperature of the second section of machine barrel section is 190-210 ℃, the temperature of the third section of machine barrel section is 200-230 ℃, the temperature of the extrusion die orifice is 220-250 ℃, the rotating speed of a screw is 300-500 r/min, the melt pressure is 3.0-4.0 MPa, and the vacuum degree is-0.08-0.03 MPa; and (3) putting the granules in the step into an oven, and drying at the temperature of 80-90 ℃ for 1h to obtain the resin material for coating.

The melting point temperature test of the coating resin materials (PP resin materials) prepared in examples 1 to 9 showed that the melting point temperature of the PP resin materials prepared in examples 1 to 5 and 9 was 170 ℃ or higher, which was significantly higher than that of the conventional PP resin materials; the melting point temperature of the PP resin material prepared in example 6 to example 8 was 160 ℃ to 165 ℃. In addition, the raw materials are put into injection molding equipment to manufacture a test standard sample for testing, the tensile strength and the elongation after fracture of the sample are tested, and after the sample is put into extrusion equipment to be coated on the outer surface of the aluminum pipe, the properties of the sample such as peel strength, high and low temperature impact resistance, corrosion resistance, ultraviolet aging resistance and the like are tested, and the results are shown in the following table 1, wherein the 150 ℃ C in the high and low temperature test

2h to-40 ℃ for 2h means that the sample is placed at 150 ℃ for 2h, then at-40 ℃ for 2h, then at 150 ℃ for 2h, then at-40 ℃ for 2h, and the treatment is cycled. As can be seen from Table 1, the resin material for coating the aluminum pipe, prepared by the invention, has the advantages of extremely strong peel strength, high and low temperature impact resistance, corrosion resistance, ultraviolet aging resistance, excellent mechanical properties, extremely strong reliability and stability.

TABLE 1 Properties of the coating resin material of the present invention and results of the property test after coating on the aluminum pipe

In summary, the present application provides a resin material for coating, which uses a PP resin material as a main component, and further includes an antioxidant, a light stabilizer, titanium dioxide, a pigment, and silica. The coating resin material with excellent tensile strength, bending strength, impact strength and ageing resistance is prepared. The preparation process of the PP resin material provided by the invention is simple, no additional equipment is required to be added, and the cost is low.

In a preferred embodiment, the PP resin is formed by fusing isotactic homopolymerized PP and block copolymerization PP, so that the rigidity and low-temperature toughness of the PP can be enhanced; when the nano-scale titanium dioxide is selected as the titanium dioxide, the tensile strength, the bending strength and the impact strength of the PP are increased, and in addition, the titanium dioxide is stable in chemical property, non-toxic and good in heat resistance, can shield ultraviolet light of all bands, and enhances the ageing resistance and the ultraviolet resistance; when the silicon dioxide is preferably silicon dioxide microspheres, the PP melting point is improved, the thermal deformation temperature is increased, and meanwhile, the hardness and the heat resistance of the surface of the material are improved; adding an antioxidant TH-412S or an antioxidant TH-412S, an antioxidant 1010 and an antioxidant DSTDP according to the weight ratio of 3:1:1, the material has excellent high-temperature resistance, ageing resistance, weather resistance and discoloration resistance while the heat resistance and oxidation resistance are obviously improved, so that the material can be kept for a long time when used at a high temperature; the antioxidant uses hindered amine light stabilizer, so that the photooxidation resistance and weather resistance of the material are improved.

Although the description is given in terms of embodiments, not every embodiment includes only a single embodiment, and such description is for clarity only, and those skilled in the art will recognize that the embodiments described herein may be combined as a whole to form other embodiments as would be understood by those skilled in the art.

The above-listed detailed description is only a specific description of a possible embodiment of the present invention, and they are not intended to limit the scope of the present invention, and equivalent embodiments or modifications made without departing from the technical spirit of the present invention should be included in the scope of the present invention.