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EP-4737512-A1 - HYDROXYL-CONTAINING DOPO COMPOSITE FLAME RETARDANT, AND PREPARATION METHOD THEREFOR AND USE THEREOF

EP4737512A1EP 4737512 A1EP4737512 A1EP 4737512A1EP-4737512-A1

Abstract

Provided in the present invention is a hydroxyl-containing DOPO composite flame retardant, comprising a component A having the structure of formula (I) and a component B having the structure of formula (II). In the hydroxyl-containing DOPO composite flame retardant, the content of the component A is larger than or equal to 50 wt%, but smaller than 100 wt%, and the content of the component B is larger than 0 wt%, but smaller than or equal to 50 wt%. The composite flame retardant composed of the component A and the component B achieves the integration of high flame retardance and high physical properties in a flame-retardant material, and overcomes the defects that using the component B alone leads to low flame-retardant efficiency and that using the component A alone results in deterioration in the mechanical properties of a high polymer material.

Inventors

  • YAO, QIANG
  • SUN, Jinhao
  • LI, XUFENG
  • CAO, Weihong
  • CHU, Zhaoning

Assignees

  • Ningbo Institute of Materials Technology and Engineering, Chinese Academy of Sciences
  • Zhejiang Wansheng Co., Ltd

Dates

Publication Date
20260506
Application Date
20230731

Claims (18)

  1. A hydroxyl-containing DOPO composite flame retardant, comprising a component A having a structure of formula (I) and a component B having a structure of formula (II), wherein R 1 and R 2 are independently selected from C 1 -C 18 alkylene, and optionally, any hydrogen atom on the alkylene is independently substituted with C 1 -C 8 alkyl or C 6 -C 18 aryl; R 3 and R 4 are independently selected from hydrogen, C 1 -C 18 alkyl, C 3 -C 18 heteroaryl, and C 6 -C 24 aryl, and optionally, any hydrogen atom on an aromatic ring of the aryl or heteroaryl is independently substituted with any C 1 -C 18 alkyl; and x and y are independently selected from 0, 1, 2, 3, and 4.
  2. The hydroxyl-containing DOPO composite flame retardant according to claim 1, wherein R 1 and R 2 are independently selected from C 1 -C 8 alkylene, and optionally, any hydrogen atom on the alkylene is independently substituted with C 1 -C 8 alkyl; R 3 and R 4 are independently selected from hydrogen, C 1 -C 8 alkyl, C 3 -C 18 heteroaryl, and C 6 -C 18 aryl.
  3. The hydroxyl-containing DOPO composite flame retardant according to claim 1 or 2, wherein R 1 and R 2 are independently selected from methylene, ethylene, propylene, butylene, methyl-substituted methylene, dimethyl-substituted methylene, ethyl-substituted methylene, methyl-substituted ethylene, dimethyl-substituted ethylene, methyl-substituted propylene, dimethyl-substituted propylene, and propyl-substituted propylene; R 3 and R 4 are independently selected from hydrogen, methyl and ethyl.
  4. The hydroxyl-containing DOPO composite flame retardant according to claim 1, wherein in the hydroxyl-containing DOPO composite flame retardant, the content of the component A is larger than or equal to 50 wt%, but smaller than 100 wt%, and the content of the component B is larger than 0 wt%, but smaller than or equal to 50 wt%.
  5. The hydroxyl-containing DOPO composite flame retardant according to claim 1 or 4, wherein in the hydroxyl-containing DOPO composite flame retardant, the content of the component A is larger than or equal to 82 wt%, but smaller than 100 wt%, and the content of the component B is larger than 0 wt%, but smaller than or equal to 18 wt%.
  6. A preparation method for the hydroxyl-containing DOPO composite flame retardant according to claim 1, the preparation method comprising the following steps: reacting a compound having a structure of formula (III) with an aliphatic cyclic diketone compound having a structure of formula (IV), and then purifying a reaction product to obtain a mixed product containing the component A having the structure of formula (I) and the component B having the structure of formula (II); wherein R 3 and R 4 are independently selected from hydrogen, C 1 -C 18 alkyl, C 3 -C 18 heteroaryl, and C 6 -C 24 aryl, and optionally, any hydrogen atom on an aromatic ring of the aryl or heteroaryl is independently substituted with any C 1 -C 18 alkyl; and x and y are independently selected from 0, 1, 2, 3, and 4; wherein R 1 and R 2 are independently selected from C 1 -C 18 alkylene, and optionally, any hydrogen atom on the alkylene is independently substituted with C 1 -C 8 alkyl or C 6 -C 18 aryl.
  7. The preparation method according to claim 6, wherein the compound having the structure of formula (III) is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.
  8. The preparation method according to claim 6, wherein the aliphatic cyclic diketone compound having the structure of formula (IV) is one or more selected from cyclohexanedione, cyclobutanedione, cyclopentanedione, cycloheptanedione, cyclooctanedione, methylcyclohexanedione, dimethylcyclohexanedione, propylcyclohexanedione, tetramethylcyclobutanedione, methylcyclopentanedione, dimethylcyclopentanedione, and ethylcyclopentanedione.
  9. The preparation method according to claim 6, wherein a molar ratio of the compound having the structure of formula (III) to the aliphatic cyclic diketone compound having the structure of formula (IV) is 1.5-10:1.
  10. The preparation method according to claim 6, wherein reaction time is between 0.01 h and 25 h, and reaction temperature ranges from 5°C to 250°C.
  11. A preparation method for the hydroxyl-containing DOPO composite flame retardant according to claim 1, the preparation method comprising the following steps: physically mixing the component A having the structure of formula (I) and the component B having the structure of formula (II), wherein in the mixture, the content of the component A is larger than or equal to 50 wt%, but smaller than 100 wt%, and the content of the component B is larger than 0 wt%, but smaller than or equal to 50 wt%.
  12. The preparation method according to claim 11, wherein a method for preparing the component A having the structure represented by formula (I) comprises the following steps: reacting a compound having a structure of formula (III) with an aliphatic cyclic diketone compound having a structure of formula (IV) under controlled conditions, and then purifying the reaction product to obtain the compound A having the structure represented by formula (I); and a method for preparing the component B having the structure represented by formula (II) comprises the following steps: reacting the compound having the structure of formula (III) with the aliphatic cyclic diketone compound having a structure of formula (IV) under controlled conditions, and then purifying the reaction product to obtain the compound B having the structure represented by formula (II); wherein R 3 and R 4 are independently selected from hydrogen, C 1 -C 18 alkyl, C 3 -C 18 heteroaryl, and C 6 -C 24 aryl, and optionally, any hydrogen atom on an aromatic ring of the aryl or heteroaryl is independently substituted with any C 1 -C 18 alkyl; and x and y are independently selected from 0, 1, 2, 3, and 4; wherein R 1 and R 2 are independently selected from C 1 -C 18 alkylene, and optionally, any hydrogen atom on the alkylene is independently substituted with C 1 -C 8 alkyl or C 6 -C 18 aryl.
  13. A flame-retardant polymer material, comprising a polymer material and the hydroxyl-containing DOPO composite flame retardant according to claim 1.
  14. The flame-retardant polymer material according to claim 13, wherein a mass fraction of the hydroxyl-containing DOPO composite flame retardant in the flame-retardant polymer material ranges from 1 wt% to 50 wt%.
  15. A flame-retardant epoxy resin, comprising the hydroxyl-containing DOPO composite flame retardant according to claim 1, an epoxy compound and a curing agent.
  16. A preparation method for the flame-retardant epoxy resin according to claim 15, comprising the following steps: melting and stirring the epoxy compound, the curing agent and the hydroxyl-containing DOPO composite flame retardant for 0.1 h to 4 h at a temperature between room temperature and 120°C, and then curing for 0.5 h to 8 h at a temperature between 70°C and 90°C, curing for 0.5 h to 8 h at a temperature between 110°C and 130°C, and finally curing for 0.5 h to 8 h at a temperature between 160°C and 180°C, and cooling naturally to obtain the flame-retardant epoxy resin.
  17. A low-dielectric flame-retardant resin composition, comprising 100 parts by weight of vinyl polyphenylene ether resin and 5 to 150 parts by weight of the hydroxyl-containing DOPO composite flame retardant according to claim 1.
  18. The low-dielectric flame-retardant resin composition according to claim 17, wherein the low-dielectric flame-retardant resin composition has a dielectric loss factor lower than that of a composition comprising the vinyl polyphenylene ether resin but not comprising the hydroxyl-containing DOPO composite flame retardant.

Description

TECHNICAL FIELD The present invention belongs to the technical field of flame retardant preparation, and relates to a hydroxyl-containing DOPO composite flame retardant, and a preparation method therefor and a use thereof. DESCRIPTION OF RELATED ART With the rapid rise of polymer material science, polymer materials have been widely used in human production and life. Since most of the polymer materials are flammable, more and more fires are caused by the ignition of polymer materials. Therefore, the flame retardance of polymer materials have been widely concerned. Polymer materials themselves cannot meet the requirements of regulations on flame retardance, and flame retardants often need to be added to achieve the purpose of flame retardance. Recently, halogen-free flame retardants such as phosphorus-based flame retardants have achieved substantial development due to the need of environmental protection. Especially 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide (DOPO) and derivatives thereof have attracted considerable attention owing to their high flame-retardant efficiency, low toxicity, and minimal impact on the properties of polymer materials. The reported DOPO derivatives can be divided into reactive and additive types: reactive derivatives have reactive groups (such as carboxyl and hydroxyl groups) attached to phosphorus substituents; in contrast, additive derivatives are structurally inert with the absence of reactive functional groups. Chinese Patent Publication No. CN100366627C reports DiDOPO with a hydroxyalkyl-substituted vinylene bridge chain structure, where the hydroxyl group is distant from the phosphorus atom. The DiDOPO, with high reactivity, is capable of undergoing transesterification with carboxylic acids or esters. Chinese Patent Publication No. CN104086593B reports the preparation of DiDOPO with a phenylene bridge chain structure by addition of a semi-aryl ketone and DOPO. The reaction process proceeds as follows: first, DOPO reacts with ketone group to form an α-hydroxyphosphine compound; subsequently, the hydroxyl group undergoes dehydration with heating to generate a vinyl phosphonate, thereby introducing a second DOPO moiety. Chinese Patent Publication No. CN106366128B introduces allyloxy group by using hydroxyl group of an α-hydroxyphosphine compound, which has high reactivity. Moreover, the patent specifically points out that hydroxyl-containing phosphaphenanthrene compounds are not suitable for low-dielectric systems (with a dielectric loss of less than 0.010). It can be concluded from the patent that the introduction of hydroxyl group is not an option unless it is for the purpose of reaction. Japanese Patent Publication Nos. JPH11-106619 and JP2001270993 and Chinese Patent Publication No. CN102428091B report DiDOPO having an inert bridge chain structure without reactive functional groups. PCT Patent Application No. WO2013020696A2 and Chinese Patent Publication No. CN109851639B report DOPO derivatives containing P-N bonds. These derivatives can be used as additive flame retardants. Known reactive DOPO derivatives need to further react with polymers or monomers for use, which is not conducive to flame retardant modification of known polymer materials, and the different reactivity of such derivatives with the polymers or monomers leads to poor performance controllability and high costs. Additive DOPO derivatives have a greater impact on the physical properties of flame-retardant polymer materials. For instance, U.S. Patent No. US8536256B2 discloses that the incorporation of DiDOPO with a vinylene bridge chain structure reduces the glass transition temperature (Tg) of epoxy resin from the range of 163°C to 172 °C to a range of 126 °C to 131 °C, which fails to meet the requirements of lead-free soldering and thus limits the scope of application of the epoxy resin. In addition, Chinese Patent Publication No. CN106366128B points out that the presence of hydroxyl group is detrimental to the dielectric loss factor (Df) of flame-retardant polymer materials, making such polymer materials difficult to use in copper-clad laminates with low dielectric loss. Based on the above analysis, the known reactive and additive DOPO derivatives are still difficult to meet the requirements of thermal and chemical stability and small impact on the physical properties of flame-retardant polymer materials, and the known processes for preparing DOPO derivatives are complex and costly. It is still desired to develop a flame retardant with simple preparation process, high atom efficiency, good flame retardance, little impact on the physical properties of flame-retardant polymer materials and even capable of improving the electrical properties of flame retardant systems. BRIEF SUMMARY OF THE INVENTION An objective of the present invention is to address the defects in the prior art, and to provide a hydroxyl-containing DOPO composite flame retardant, and a preparation method therefor and a use thereof for th