Search

EP-4737465-A1 - DOPO DERIVATIVE FLAME RETARDANT CONTAINING ALPHA-HYDROXYL AND HAVING CYCLIC STRUCTURE AS BRIDGE CHAIN, PREPARATION METHOD FOR DOPO DERIVATIVE FLAME RETARDANT, AND USE OF DOPO DERIVATIVE FLAME RETARDANT

EP4737465A1EP 4737465 A1EP4737465 A1EP 4737465A1EP-4737465-A1

Abstract

The present invention provides a DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain. The DOPO derivative flame retardant has a structure represented by formula (I). In formula (I), R 1 and R 2 are independently selected from C 1 -C 18 alkylene; 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 x and y are independently selected from 0, 1, 2, 3, and 4. The DOPO derivative flame retardant has a simple and convenient preparation method, high atom efficiency and good flame retardance, and can retain excellent physical properties of a polymer material.

Inventors

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

Assignees

  • Ningbo Institute Of Material Technology And Engineering Chinese Academy of Sciences
  • Zhejiang Wansheng Co., Ltd

Dates

Publication Date
20260506
Application Date
20230731

Claims (16)

  1. A DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain, which has a structure represented by formula (I) below: 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 DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain 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 DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain 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. A preparation method for the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain according to claim 1, the preparation method comprising the following step: reacting a compound having a structure of formula (II) with an aliphatic cyclic diketone compound having a structure of formula (III) to obtain the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain; 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.
  5. The preparation method according to claim 4, wherein the compound having the structure of formula (II) is 9,10-dihydro-9-oxa-10-phosphaphenanthrene-10-oxide.
  6. The preparation method according to claim 4, wherein the aliphatic cyclic diketone compound having the structure of formula (III) is one or more selected from cyclohexanedione, cyclobutanedione, cyclopentanedione, cycloheptanedione, cyclooctanedione, methylcyclohexanedione, dimethylcyclohexanedione, propylcyclohexanedione, tetramethylcyclobutanedione, methylcyclopentanedione, dimethylcyclopentanedione, and ethylcyclopentanedione.
  7. The preparation method according to claim 4, wherein a molar ratio of the compound having the structure of formula (II) to the aliphatic cyclic diketone compound having the structure of formula (III) is 2-20: 1.
  8. The preparation method according to claim 4, wherein reaction time is between 0.01 h and 25 h, and reaction temperature ranges from 5°C to 250°C.
  9. A flame-retardant polymer material, comprising a polymer material and the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain according to claim 1.
  10. The flame-retardant polymer material according to claim 9, wherein a mass fraction of the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain in the flame-retardant polymer material ranges from 1 wt% to 50 wt%.
  11. The flame-retardant polymer material according to claim 9, wherein the flame-retardant polymer material comprises the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain and a phosphorus-based flame retardant, and a mass ratio of the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain to the phosphorus-based flame retardant is 1-20:1.
  12. A low-dielectric flame-retardant resin composition, comprising 100 parts by weight of vinyl polyphenylene ether resin and 2 to 150 parts by weight of the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain according to claim 1.
  13. The low-dielectric flame-retardant resin composition according to claim 12, 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 DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain.
  14. The low-dielectric flame-retardant resin composition according to claim 12, wherein the low-dielectric flame-retardant resin composition comprises the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain and a phosphorus-based flame retardant, and a mass ratio of the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain to the phosphorus-based flame retardant is 1-20:1.
  15. A flame-retardant epoxy resin, comprising the DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain 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 DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain 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 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.

Description

TECHNICAL FIELD The present invention belongs to the technical field of flame retardant preparation, and relates to a DOPO derivative flame retardant containing α-hydroxyl and having a cyclic structure as a bridge chain, a preparation method for the DOPO derivative flame retardant, and a use of the DOPO derivative flame retardant. 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 D