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CN-121975310-A - Toughened nylon for high-pressure resin pipe and preparation method thereof

CN121975310ACN 121975310 ACN121975310 ACN 121975310ACN-121975310-A

Abstract

The application discloses toughened nylon for a high-pressure resin pipe and a preparation method thereof, and relates to the technical field of high polymer materials. The modifier containing carboxyl and hydroxyl is esterified with hydroxyl-containing monomer and then is reacted with epoxy-containing grafting agent (ring-opening reaction to prepare modified toughening agent A, the mass ratio of the modified toughening agent A to the epoxy-containing grafting agent A is controlled to be 1 (1.5-3) (1.5-2), so that a rigid-flexible molecular structure is realized.

Inventors

  • SUN PEIZHU
  • LIU YIQUN
  • CUI JIWEN

Assignees

  • 利通希法(青岛)新材料科技有限公司

Dates

Publication Date
20260505
Application Date
20260202

Claims (10)

  1. 1. The toughened nylon for the high-pressure resin pipe is characterized by comprising, by weight, 60-70 parts of polydodecyl amide, 10-20 parts of polycaprolactam, 5-20 parts of modified toughening agent A, 5-20 parts of toughening agent B, 0.01-3 parts of compatilizer, 0.1-0.5 part of antioxidant and 0.1-0.5 part of lubricant, wherein the modified toughening agent A comprises hydroxyl-containing monomers, epoxy-containing grafting agents and carboxyl-and hydroxyl-containing modifiers.
  2. 2. The toughened nylon for high pressure resin pipes as claimed in claim 1, wherein the mass ratio of said modified toughening agent A, toughening agent B to compatibilizing agent is (5-15): 3.
  3. 3. The toughened nylon for high pressure resin pipes as claimed in claim 1, wherein the mass ratio of said modifier containing carboxyl groups and hydroxyl groups, said monomer containing hydroxyl groups and said grafting agent containing epoxy groups is 1 (1.5-3): 1.5-2.
  4. 4. The toughened nylon for high pressure resin pipes as described in claim 1, wherein said modifier containing carboxyl groups and hydroxyl groups is any one of 4-amino-3, 5-dihydroxybenzoic acid, 3, 5-dihydroxy-4-methylbenzoic acid and p-carboxyphenylphosphonic acid.
  5. 5. The toughened nylon for high pressure resin pipes as claimed in claim 1, wherein said epoxy group-containing grafting agent is any one of methyl epichlorohydrin and octyl glycidyl ether.
  6. 6. The toughened nylon for high pressure resin pipes as described in claim 1, wherein said hydroxyl group-containing monomer is any one of glycerol monooleate and ricinoleic alcohol.
  7. 7. The toughened nylon for high pressure resin pipes as claimed in claim 1, wherein said modified toughening agent a is prepared by a process comprising the steps of: S1, mixing a modifier containing carboxyl and hydroxyl and a monomer containing hydroxyl, dissolving in a first solvent, adding a catalyst, introducing inert gas, heating and stirring, filtering, washing, and vacuum drying to obtain an intermediate; S2, mixing the intermediate prepared in the step S1 with a grafting agent containing epoxy groups, dissolving in a second solvent, introducing inert gas, heating, stirring, heating, adding an alkali solution, stirring, decompressing, filtering, washing, and drying in vacuum to obtain the modified toughening agent.
  8. 8. The toughened nylon for high pressure resin pipes as described in claim 7, wherein the heating temperature in said step S1 is 160 to 180℃and the heating temperature during heating and stirring in said step S2 is 60 to 80 ℃.
  9. 9. The toughened nylon for high pressure resin pipes as described in claim 7, wherein the stirring speed in said step S1 and step S2 is 300-700rpm and the stirring time is 5-9 hours.
  10. 10. The method for producing toughened nylon for high pressure resin pipes as claimed in any of claims 1 to 9, comprising the steps of: and mixing the polydodecyl lactam, the polycaprolactam, the compatilizer, the modified toughening agent A and the toughening agent B, adding the lubricant and the antioxidant, uniformly mixing, carrying out melt extrusion, cooling to room temperature, and granulating to obtain the toughened nylon for the high-pressure resin pipe.

Description

Toughened nylon for high-pressure resin pipe and preparation method thereof Technical Field The application relates to the technical field of high polymer materials, in particular to toughened nylon for a high-pressure resin pipe and a preparation method thereof. Background With the advanced advancement of global energy development and chemical industry, the high-pressure resin pipe is used as a core component of a fluid conveying system, and the application range of the high-pressure resin pipe is expanded from the traditional land industry to the extreme working condition fields of deep sea oil gas exploitation, polar resource exploration, liquefied natural gas storage and transportation and the like. The pipe needs to resist the comprehensive test of external mechanical damage, chemical medium erosion and complex thermal environment. Nylon materials, by virtue of their excellent wear resistance, self-lubricity, chemical resistance and relatively low density, exhibit unique advantages in the manufacture of high pressure resin pipes, particularly in the case of carbon chain and lactam-like polymers such as polydodeolactam and polycaprolactam, whose molecular segment regularity imparts higher tensile strength and rigid structure to the pipe. However, engineering practice repeatedly has problems, and polycaprolactam systems have intrinsic defects that the density of hydrogen bonds among molecular chains is too high, the crystallization rate is high, and the spherulites are large in size, so that the chain segment movement capability of the material in a low-temperature environment is sharply limited, the toughness is remarkably attenuated, the notch impact strength is suddenly reduced, the elongation at break is sharply reduced, and once external impact or internal pressure pulsation is encountered, brittle fracture is extremely easy to induce, and catastrophic leakage is formed. The short plate is especially fatal in severe cold areas or deep sea delivery and distribution systems, and when the pipe is exposed to outdoor environments in polar winter or severe temperature change areas near deep sea hot fluid nozzles, the internal stress concentration of the material is overlapped with a low-temperature embrittlement effect, so that the service life is greatly shortened. More seriously, modern industry safety regulations place multiple demands on tubing for the delivery of combustible media. For example, a pipeline vertically extends from a heat-insulating cabin of a platform deck to a submarine wellhead with the depth of hundreds of meters, a continuous temperature gradient from normal temperature to deep sea water temperature is experienced along the way, seawater convection is aggravated in winter so that the outer layer of a pipe wall is kept below a freezing point for a long time, and high-pressure methanol or glycol hydrate inhibitor conveyed inside causes local supercooling, so that a complex problem is formed by thermal stress caused by internal and external temperature difference and fluid pulsation impact. Meanwhile, hydrocarbon leakage and open flame risks exist in a process area on the upper part of the platform, once a fire spreads to a pipeline support area, the outer wall of the pipe needs to resist radiant heat flow and convection heating of high-temperature flame within a few minutes, heat is prevented from penetrating through the pipe wall to reduce the glass transition temperature of the inner nylon matrix, and the loss of bearing capacity is avoided. Disclosure of Invention The application aims to provide toughened nylon for a high-pressure resin pipe, which has good toughness at low temperature and good flame retardant effect, and is favorable for adapting to different scene requirements. In a first aspect, the present application provides a toughened nylon for high pressure resin pipes and a preparation method thereof, which adopts the following technical scheme: A toughened nylon for high-pressure resin pipes comprises, by weight, 60-70 parts of polydodecyl, 10-20 parts of polycaprolactam, 5-20 parts of a modified toughening agent A, 5-20 parts of a toughening agent B, 0.01-3 parts of a compatilizer, 0.1-0.5 part of an antioxidant and 0.1-0.5 part of a lubricant, wherein the modified toughening agent A comprises a hydroxyl-containing monomer, an epoxy-containing grafting agent and a carboxyl-and hydroxyl-containing modifier. By adopting the technical scheme, the modified toughening agent A is prepared by reacting a modifier containing carboxyl and hydroxyl, a monomer containing hydroxyl and a monomer containing epoxy. The carboxyl in the modifier containing carboxyl and hydroxyl and the hydroxyl of castor oil are subjected to esterification reaction to generate an intermediate containing hydroxyl, and the hydroxyl in the intermediate and epoxy chloropropane are subjected to epoxy ring-opening reaction to finally prepare the modified toughening agent. When the modified toughening agent A