阅读说明：本技术 一种高压储气瓶塑料内胆 (Plastic inner container of high-pressure gas storage bottle ) 是由 严兵 胡世国 吴世超 祁震 张继维 唐许 施刘生 张可可 蔡少雷 何郅晴 于 2021-09-08 设计创作，主要内容包括：本发明公开了一种高压储气瓶塑料内胆,包含由内至外依次设置的第一柔性层A、第一刚性层B、第二刚性层C和第二柔性层D。本发明的高压储气瓶塑料内胆,其生产效率高,刚性、韧性、性能稳定性好；与复合材料树脂基材外壳的粘附力好,可以达成更高的耐压能力；且进一步可在内部施加密着性良好的涂层以得到更高的气密性。本发明还提供使用上述的高压储气瓶塑料内胆的储气瓶,包括氢气瓶、氮气瓶、氧气瓶、氩气瓶等。(The invention discloses a plastic liner of a high-pressure gas cylinder, which comprises a first flexible layer A, a first rigid layer B, a second rigid layer C and a second flexible layer D which are sequentially arranged from inside to outside. The plastic liner of the high-pressure gas cylinder has high production efficiency, and good rigidity, toughness and performance stability; the adhesive force with the composite material resin base material shell is good, and higher pressure resistance can be achieved; and further a coating with good adherence can be applied inside to obtain higher airtightness. The invention also provides a gas cylinder using the plastic liner of the high-pressure gas cylinder, which comprises a hydrogen cylinder, a nitrogen cylinder, an oxygen cylinder, an argon cylinder and the like.)

1. The plastic liner of the high-pressure gas cylinder is characterized by comprising a first flexible layer A, a first rigid layer B, a second rigid layer C and a second flexible layer D which are sequentially arranged from inside to outside.

2. The plastic liner of a high-pressure gas cylinder as claimed in claim 1, wherein the first flexible layer a and the second flexible layer D respectively comprise one or more of polyurethane, ethylene-vinyl acetate copolymer, and polyolefin.

3. The plastic liner of a high-pressure gas cylinder as claimed in claim 1, wherein the first rigid layer B and the second rigid layer C respectively contain one or more of polyphenylene sulfide, polyetheretherketone, polyimide and polyamide.

4. The plastic liner of claim 3, wherein the first rigid layer B comprises polyphenylene sulfide and the second rigid layer C comprises polyamide.

5. The plastic liner for a high-pressure gas cylinder as claimed in any one of claims 3 or 4, wherein the polyphenylene sulfide is one or more of poly-p-phenylene sulfide, poly-p-phenylene sulfide-m-phenylene sulfide copolymer, and poly-p-phenylene sulfide-arylene sulfide copolymer.

6. The plastic liner of a high-pressure gas cylinder as claimed in claim 1, wherein at least one of the first rigid layer B and the second rigid layer C contains one or more of carbon fiber, glass fiber and organic fiber.

7. The plastic liner of a high-pressure gas cylinder as claimed in claim 1, wherein the thickness ratio of the first rigid layer B to the second rigid layer C is 1: 1.5-1: 5.

8. The method for forming the plastic liner of the high-pressure gas cylinder according to any one of claims 1 to 7, comprising the following steps: and (3) co-extruding the raw materials of the first flexible layer A, the first rigid layer B, the second rigid layer C and the second flexible layer D to form a multi-layer composite parison, and then forming a hollow plastic liner structure by blowing.

9. The method of claim 8, wherein the multi-layer composite parison is cooled after leaving the extrusion die orifice in the co-extrusion process, the cooling rate being 50 ℃/s or higher.

10. A gas cylinder comprising the plastic liner of a high pressure gas cylinder according to any one of claims 1 to 9.

Technical Field

The invention relates to the field of high-pressure gas storage materials, in particular to a plastic inner container of a gas storage bottle.

Background

A fuel cell vehicle is a vehicle that generates electric power as power using an on-vehicle fuel cell device that can directly convert chemical energy of a fuel (such as hydrogen gas, natural gas) and an oxidant into electric energy through an electrode reaction. The fuel cell automobile has the advantages of zero emission, low noise, wide fuel source, long endurance, high power generation efficiency and the like.

With the strong support of national policy and the progress of technology, the development of fuel cell automobile industry in China is continuously increasing in temperature. The development of the fuel cell automobile is beneficial to reducing the external dependence of energy in China, reducing the pollution emission in the field of transportation and supplementing the short plates of the pure electric automobile in the commercial fields of long-distance heavy load and the like. The fuel cell automobile in China is estimated to reach the scale of 5-10 thousands in 2025, and million fuel cell automobiles are commercially applied in 2030.

High-pressure gas storage cylinders for storing fuels such as hydrogen and natural gas are important parts of fuel cell vehicles. Structurally, gas cylinders can be currently divided into 4 types:

type I: all-metal structures, typically steel.

Type II: mainly metal, and is wrapped by some fiber composite materials in the circumferential direction.

Type III: the inner layer is a metal liner, and the outer layer is completely wrapped by composite materials.

Type IV: the inner layer is a polymer inner container, and the outer layer is completely wrapped by the composite material.

Among them, type III and type IV can withstand high pressure of 30MPa or more, and thus can be applied to fuel cell vehicles. Particularly, compared with the type III gas storage cylinder, the type IV gas storage cylinder has higher hydrogen storage density, lower cost and wider application prospect.

Various technical schemes for the inner container of the IV-type gas cylinder are disclosed.

CN111645370A discloses a 3-layer inner container, wherein the inner layer and the outer layer are mainly polyamide 6, and the middle layer is ethylene-vinyl alcohol copolymer. This technical proposal improves the gas barrier property of the single-layer polyamide 6 liner, but has the problems of low rigidity and insufficient pressure resistance.

JP2011-185340a discloses a pressure vessel based on polyphenylene sulfide, which has high rigidity and good pressure resistance. However, the toughness is poor and the reliability is insufficient upon impact. And the technical proposal is that the pressure vessel is manufactured by an injection molding method. The liner manufactured by the injection molding method has the problems of uneven internal performance of the product and low manufacturing speed.

Therefore, the prior art lacks a plastic liner of a high-pressure gas cylinder, which has rigidity, toughness and air tightness, and has simple and efficient manufacturing method, uniform and reliable performance of a finished product.

Disclosure of Invention

The invention provides a plastic liner of a high-pressure gas cylinder, which has high production efficiency, good rigidity, toughness and performance stability; the adhesive force with the composite material resin base material shell is good, and higher pressure resistance can be achieved; and further a coating with good adherence can be applied inside to obtain higher airtightness.

In order to achieve the purpose, the invention adopts the following technical scheme:

the invention provides a plastic liner of a high-pressure gas cylinder, which comprises a first flexible layer A, a first rigid layer B, a second rigid layer C and a second flexible layer D which are sequentially arranged from inside to outside.

The first flexible layer A has good toughness, has good adhesion with the first rigid layer B, is also suitable for coextrusion and inflation processing, and shows better adhesion with the coating layer when the coating layer is additionally arranged on the outer surface of the first flexible layer A to increase the air tightness of the liner.

The second flexible layer D has good toughness and good adhesion to the second rigid layer C, and is also suitable for coextrusion and inflation processing. And the fiber is easily arranged outside the shell in a winding mode to prepare the composite material resin substrate shell, and the adhesion force of the composite material resin substrate shell and the shell is also good.

The first flexible layer A and the second flexible layer D respectively contain one or more of polyurethane, ethylene-vinyl acetate copolymer and polyolefin.

The polyurethanes are crosslinked polymers of urethane groups in the repeat units and can be obtained by copolymerizing polyesters, polyethers or urethane oligomers with di-or polyisocyanates. Thermoplastic polyurethane is preferable in view of molding processability.

The first rigid layer B and the second rigid layer C respectively have good rigidity and toughness, and the adhesion with the first flexible layer A and the second flexible layer D on two sides is good.

The first rigid layer B and the second rigid layer C respectively contain one or more of polyphenylene sulfide, polyether ether ketone, polyimide and polyamide.

In view of further improving the air tightness and durability of the plastic liner of the high-pressure gas cylinder, the first rigid layer B preferably contains polyphenylene sulfide.

It is further preferred that the polyphenylene sulfide is one or more of a poly (p-phenylene sulfide), a poly (p-phenylene sulfide) -m-phenylene sulfide copolymer, and a poly (p-phenylene sulfide) -arylene sulfide copolymer.

The poly (p-phenylene sulfide) -m-phenylene sulfide copolymers and poly (p-phenylene sulfide) -arylene sulfide copolymers are more suitable for coextrusion and inflation processing than poly (p-phenylene sulfide), but have lower rigidity.

In order to optimize rigidity and processability, it is preferable that the first rigid layer B contains polyphenylene sulfide, and the polyphenylene sulfide is one or more of poly-p-phenylene sulfide, poly-p-phenylene sulfide-m-phenylene sulfide copolymer, and poly-p-phenylene sulfide-arylene sulfide copolymer.

The first rigid layer B further contains poly-p-phenylene sulfide, and one or two of poly-p-phenylene sulfide-m-phenylene sulfide copolymer and poly-p-phenylene sulfide-arylene sulfide copolymer. Further preferably, one or both of the poly-p-phenylene sulfide-m-phenylene sulfide copolymer and the poly-p-phenylene sulfide-arylene sulfide copolymer are 100 to 300 parts by weight based on 100 parts by weight of the poly-p-phenylene sulfide in the first rigid layer B.

In view of further improving the processing performance and the air tightness of the plastic liner of the high-pressure gas cylinder, the second rigid layer C preferably contains polyamide. Preferably, the polyamide is polyamide 6.

Further, at least one of the first rigid layer B and the second rigid layer C preferably contains one or more of carbon fiber, glass fiber, and organic fiber to further improve the rigidity and toughness of the two layers.

More preferably, at least one of the first rigid layer B and the second rigid layer C contains carbon fibers; most preferably, the first rigid layer B and the second rigid layer C both contain carbon fibers.

The content of the fibers can be changed according to actual requirements, and is preferably 0-40% by weight.

The thicknesses of the first flexible layer A, the first rigid layer B, the second rigid layer C and the second flexible layer D are not limited and can be reasonably selected according to actual needs. In view of sufficiently exhibiting the performance of each layer, the thickness ratio of the first rigid layer B to the second rigid layer C is preferably 1:1.5 to 1:5, and the thickness ratio of the first flexible layer a, the first rigid layer B, and the second flexible layer D is preferably: 0.1:1: 0.1-0.5: 1: 0.5.

The invention also provides a method for forming the plastic liner of the high-pressure gas cylinder, which comprises the following steps: and (3) co-extruding the raw materials of the first flexible layer A, the first rigid layer B, the second rigid layer C and the second flexible layer D to form a multi-layer composite parison, and then forming a hollow plastic liner structure by blowing.

The coextrusion can adopt general equipment and select reasonable parameters according to actual requirements to manufacture the multilayer composite parison. In view of improving the blow-up property of the multilayer composite parison to obtain a plastic liner having more excellent properties, it is preferable that the multilayer composite parison is cooled after leaving the extrusion die in the coextrusion process at a cooling rate of 50 ℃/s or more, more preferably 100 ℃/s or more. The multilayer composite parison can be cooled in a cold roll rolling mode, and the cooling speed can be adjusted by adjusting the temperature, the diameter and the material of the cold roll.

The invention also provides a gas cylinder using the plastic liner of the high-pressure gas cylinder, which comprises a hydrogen cylinder, a nitrogen cylinder, an oxygen cylinder, an argon cylinder and the like

Compared with the prior art, the invention has the beneficial effects that:

1. the plastic liner of the high-pressure gas cylinder has good air tightness, rigidity, toughness and durability.

2. The plastic liner of the high-pressure gas cylinder has good adhesion with the composite material resin base material shell.

3. The coating layer can be further applied to the inner side of the plastic liner of the high-pressure gas cylinder so as to further improve the performances of air tightness and the like.

4. The plastic liner of the high-pressure gas storage bottle can be prepared by coextrusion and inflation processes, and has good processing universality and high production efficiency.

Detailed Description

The technical solutions in the embodiments of the present invention will be clearly and completely described below, and it is obvious that the described embodiments are only a part of the embodiments of the present invention, and not all embodiments.

The method for testing the plastic liner of the high-pressure gas cylinder prepared in each embodiment and the comparative example comprises the following steps:

[ formability ]

And carrying out blow molding on the multilayer composite parison. And adjusting the blow molding conditions to determine the maximum blow ratio capable of stably processing. The blow-up ratio is more than 8, and the formability is 0 grade; the blow-up ratio is 4-7, and the formability is 1 grade. The blow-up ratio is 2-3, and the formability is 2-grade. And the optimal level 0.

[ flexural Strength ]

Bending strength: the test speed is 10mm/min according to GB/T2567-2008 test.

[ impact strength ]

The sample was processed into sample 1 and the notched sample was type A as determined in GB/T10431993.

[ bonding force to coating ]

Each sample to be tested was cut into a specimen having a length of 10cm by a width of 2.5 cm. The Trijing chemical Takelac WPB-341 was applied to the inner surface of the spline (i.e., the surface that was in contact with the stored gas when the bladder was in use) to form a coating about 10 μm thick. The binding force is tested by the Baige method, and the grade is 0-5 according to GB/T9286-plus 1998. And the optimal level 0.

[ MEANS FOR BINDING TO EPOXY RESIN ]

And the adhesion force with the shell of the composite material resin substrate is represented by the binding force with the epoxy resin. Each sample to be tested was cut into a specimen having a length of 10cm by a width of 2.5 cm. Using a suitable mold, bisphenol A type epoxy resin (EPICLON HM-091, available from DIC corporation, equivalent ethylene diamine as a curing agent) having a length of 8cm, a width of 2cm and a thickness of 0.5cm was cast onto the outer surface of the sample piece (i.e., the surface to which the outer shell of the composite resin substrate was adhered when the inner container was further molded into a high-pressure gas cylinder), and cured in a forced air oven at 50 ℃ for 7 hours to obtain an epoxy resin/sample laminate.

Measured by using a pull force tester according to GB/T5210-2006. The average value of the pulling force was determined at random 5 points on the sample.

The average value of the drawing force is more than 10MPa and is 0 grade, 7 MPa-9 MPa is 1 grade, and the average value of the drawing force is less than 6MPa and is 2 grade. And the optimal level 0.

The high-pressure gas cylinder plastic liner prepared by each embodiment and comparative example comprises the following raw materials in layers:

[ first Flexible layer A ]

A1: thermoplastic polyurethane.

A2: ethylene-vinyl acetate copolymer.

[ first rigid layer B ]

B1: poly (p-phenylene sulfide).

B2: poly (p-phenylene sulfide) -m-phenylene sulfide copolymers.

B3: contains 30 wt% of poly-p-phenylene sulfide and 70 wt% of poly-p-phenylene sulfide-m-phenylene sulfide copolymer.

B4: contains 21 wt% of poly-p-phenylene sulfide, 49 wt% of poly-p-phenylene sulfide-m-phenylene sulfide copolymer and 30 wt% of carbon fiber short fiber.

B5: and (3) polyamide 6.

B6: contains 70% of polyamide 6 and 30% of carbon fiber short fibers.

[ second rigid layer C ]

C1: as in B1.

C2: as in B2.

C3: as in B3.

C4: as in B4.

C5: as in B5.

C6: as in B6.

(second Flexible layer D)

D1: as in A1.

D2: as in A2.

Examples 1 to 18

Multilayer concentric composite preforms were prepared by a set of coextrusion equipment according to the composition and structure shown in table 1. The die temperature was 300 ℃. And (3) after the multilayer composite parison leaves the extrusion die orifice, the multilayer composite parison enters a pair of cold rolls to be rolled and cooled, and the multilayer composite parison is obtained, and the thickness of the multilayer composite parison is 1 cm.

The surface temperatures T and T' of the multilayer composite parison upon entering and exiting the chill roll were measured and the multilayer composite parison cooling rate T (equation 1) was calculated from the diameter r of the chill roll and the line speed v. And the cooling rate was controlled to the value shown in table 1 by adjusting the linear velocity.

T ═ T-T') v/r formula 1

The formability was then tested by blowing to form a hollow plastic liner.

The relevant performance of the plastic liner with the blow-up ratio of 4 is measured, and the test results are shown in table 1.

Comparative examples 1 to 5

A single-layer parison was prepared by one extruder using the ingredients shown in table 1, referring to the manufacturing method of the above example. The formability was then tested by blowing to form a hollow plastic liner.

The relative performance of the plastic liner with the blow-up ratio of 4 in comparative examples 1, 3, 4 and 5 and the relative performance of the plastic liner with the blow-up ratio of 2 in comparative example 2 were measured, and the test results are shown in table 1.

According to the test results, the bending strength of comparative example 1 is too low, and the rigidity is too poor; comparative example 2 is too poor in moldability and insufficient in toughness; the formability of comparative example 3 is improved compared to comparative example 2, but the toughness is still poor; comparative examples 4 and 5 are also not excellent in moldability and poor in rigidity. Comparative examples 2, 3, 4, 5 also have the problem of poor bonding with the coating, with the epoxy resin.

The comprehensive performance of each embodiment in the aspects of formability, bending strength, impact strength, binding force with a coating and binding force with epoxy resin is obviously superior to each proportion, and the embodiment has good rigidity and toughness; the adhesive force with the composite material resin base material shell is good, and higher pressure resistance can be achieved; a polyurethane airtight coating with good adhesion can be applied inside to obtain higher airtightness; the method is suitable for the blow molding process, and has the advantages of simple method, high efficiency, uniform performance of the finished product and good reliability.

The above description is only for the preferred embodiment of the present invention, but the scope of the present invention is not limited thereto, and any person skilled in the art should be considered to be within the technical scope of the present invention, and the technical solutions and the inventive concepts thereof according to the present invention should be equivalent or changed within the scope of the present invention.

TABLE 1