JP5691157B2 - Flame retardant shape memory resin composition and precursor composition thereof - Google Patents

Description

  The present invention relates to a shape memory resin composition excellent in flame retardancy and practical physical properties and a precursor composition thereof.

  Conventionally, there are alloy materials and resin materials that show shape memory properties. Shape memory alloys are used for pipe joints and orthodontics, and shape memory resins are used for medical treatment such as heat-shrinkable tubes, clamping pins, laminate materials, and casts. It is used for appliance materials. Compared to shape memory alloys, shape memory resin has advantages such as being able to be processed into a complicated shape, having a large shape recovery rate, being lightweight, freely coloring, and being low in cost. It is expected to be applied to automobile housings, automobile parts, aircraft parts, and space development parts. Further, as the shape memory resin, since the thermosetting resin has a three-dimensional cross-linked structure by covalent bond, it is excellent in the initial shape memory property and the deformed shape restoration property. Moreover, what used the polylactic acid etc. which are plant origin resin as a base resin is excellent also in the environmental characteristic (patent documents 1, 2).

  However, in the case where the shape memory resin composition is used for applications that require high flame retardance such as housings for home appliances, OA equipment, and various parts described above, flame retardancy is necessary. In particular, when used in a housing of an electrical product, the shape memory resin composition needs to satisfy flame retardant standards such as the US UL standard. However, the existing shape memory resin composition has not been able to satisfy the flame retardant standard.

  On the other hand, as a general method, a flame retardant method comprising blending a shape memory resin with an organic flame retardant such as a halogen flame retardant such as a bromine compound having high flame retardant efficiency or a phosphorus flame retardant (Non-Patent Document 1). However, when a large amount of these flame retardants is added, these flame retardants themselves do not have shape memory properties, and shape memory properties, particularly restoration properties, are hindered. That is, the resilience of the shape memory resin is realized because the initial shape is memorized by the crosslinked structure in the resin, but the resin composition to which a large amount of a flame retardant that does not participate in crosslinking is added, Since this memory is weakened, restorability is hindered (Non-Patent Document 2).

  On the other hand, there is also a method of adding an inorganic flame retardant such as an inorganic hydroxide compound (also called a metal hydrate, which includes aluminum hydroxide), a silica compound, and antimony trioxide (Non-patent Document 1). . However, inorganic flame retardants have a weak flame retardant effect and need to be added in a large amount compared to organic flame retardants. Shape memory resin compositions are too rigid and difficult to deform. It will inhibit sex.

  There is an example (Patent Documents 3 and 4) in which a phosphazene compound, which is a phosphorus compound, is used as a flame retardant. However, since it is an additive, the characteristics of the shape memory resin are impaired. In addition, in consideration of bleeding and volatilization, an example in which a phosphazene derivative having a double bond is bonded and fixed to a resin as a flame retardant component (Patent Document 5), or a phosphazene derivative having a hydroxyl group is used in a photosensitive resin composition. Although there is an example (Patent Document 6) in which the resin is bonded and fixed, there is no use as an additive to the shape memory resin, and it is considered that the characteristics of the shape memory resin are also impaired.

WO2005 / 056642 WO2009 / 063943 JP 2006-249139 A JP 2006-193619 A WO2004 / 083295 WO2005 / 019231

Polymer flame retardant technology (published by CMC Publishing Co., Ltd., supervised by Hitoshi Nishizawa, published in 2002, Chapter 3) Material development of shape memory polymer (published by CMC Publishing Co., Ltd., supervised by Masahiro Irie, published in 2000, Chapter 1)

  The technical problem of the present invention is to provide a shape memory resin composition and a precursor composition thereof that are excellent in flame retardancy and practical physical properties.

  From the above, the present inventors have intensively studied to develop a shape memory resin composition containing a flame retardant that does not impair the characteristics of the shape memory resin and its precursor composition, and as a result, the present invention has been achieved.

That is, the present invention contains a phosphazene compound (A) having at least two functional groups and a linker (B) having two or more functional groups capable of binding to the functional groups of the phosphazene compound (A), or Shape memory resin containing a shape memory resin precursor, a phosphazene compound (A) having at least two functional groups, and a linker (B) having two or more functional groups capable of binding to the functional groups of the phosphazene compound (A) A precursor composition of the composition comprising:
The functional group of the phosphazene compound (A) is a hydroxyl group, and the functional group of the linker (B) is an isocyanate group or an epoxy group,
A shape memory resin composition in which the content of the phosphazene compound (A) is 10% by mass or more based on the total amount of the shape memory resin precursor, the phosphazene compound (A) and the linker (B) in the precursor composition. The precursor composition.

In addition, it is preferable that the phosphazene compound (A) whose functional group is a hydroxyl group is a cyclic phenyl phosphazene compound . The linker (B) is preferably a polyisocyanate compound having an isocyanuric group.

  Furthermore, the present invention is a shape memory resin composition and a molded product obtained by curing the precursor composition.

  Since the precursor composition of the shape memory resin composition of the present invention fixes the flame retardant in the resin component by covalent three-dimensional crosslinking by curing, the flame retardant does not bleed or volatilize and is cured. The molded product obtained by this method has excellent recoverability and does not hinder the shape recovery function and deformation operability, so it is useful for the manufacture of housings and automotive parts such as electronic devices that require flame resistance. is there.

  Hereinafter, the present invention will be described in more detail.

  The present invention relates to flame retardant without a problem in the shape memory property of the shape memory resin composition. That is, the precursor composition of the shape memory resin composition includes a phosphazene compound (A) having at least two functional groups and a linker (B) having two or more functional groups bonded to the functional groups. And In the precursor composition of the shape memory resin composition, the phosphazene compound (A) is 10% by mass of the total of the shape memory resin precursor, the phosphazene compound (A) and the linker (B) in the precursor composition. That's it.

  The phosphazene compound (A) used in the present invention is a flame retardant compound, and has a plurality of functional groups serving as crosslinking sites, and can form a three-dimensional structure starting from these functional groups. Is. The three-dimensional structure is formed via the linker (B). And even if this phosphazene compound (A) itself does not have another shape memory resin precursor, it can form a shape memory resin with a linker (B). Therefore, the precursor composition may be free of shape memory resin precursors other than the phosphazene compound (A).

The functional group of the phosphazene compound (A) may form a crosslink by any of an addition reaction, a condensation reaction, and a copolymerization reaction. However, in order to constitute a three-dimensional structure, each of the phosphazene compound (A) and the linker (B) needs to have a plurality of functional groups, and either one has three or more functional groups. There is a need. However, if the functional group serving as the crosslinking site can form a branched structure like an amino (NH ₂ ) group, even if it is two, a three-dimensional structure can be formed. That's all you need.

  Specific examples of such a functional group include a hydroxy group, a carboxy group, an isocyanate group, a cyanate group, an amino group, an imino group, a carbamoyl group, a succinimino group, and an epoxy group, and combinations include an amide bond and a urethane. Those that form bonds are preferred. Of these, hydroxy groups having active hydrogen are particularly preferred as the functional group of the phosphazene compound (A) when the linker (B) is a polycarboxylic acid, polyisocyanate, or the like.

  In order to exhibit shape memory properties, the phosphazene compound (A) preferably has a cyclic structure, and more preferably has a 6-membered ring structure. Moreover, since a flame retardance becomes favorable, it is preferable that the phosphazene compound (A) has a phenyl group. Therefore, a cyclic phenyl phosphazene compound is particularly preferable as the phosphazene compound (A).

  Further, the number of functional groups of the phosphazene compound (A) is at least 2, but if it is too much, the linker (B) increases and flame retardancy and shape memory properties are lowered. Yes, more preferably 4 or less, particularly preferably 3 or less.

  When the addition ratio of the phosphazene compound (A) in the shape memory resin composition to which the flame retardant is added is higher, higher flame retardancy can be obtained. The total amount of the shape memory resin precursor, the phosphazene compound (A) and the linker (B) is 10% by mass or more, and preferably 45% by mass or more.

  A preferred example of the phosphazene compound (A) is shown in the structural formula (1).

式（１）中、Ｒは、それぞれ独立に、水素、ヒドロキシ基、カルボキシ基、イソシアネート基、シアネート基、アミノ基、イミノ基、カルバモイル基、スクシンイミノ基、エポキシ基などの官能基を表し、そのうち少なくとも２つは官能基である。

In formula (1), each R independently represents a functional group such as hydrogen, hydroxy group, carboxy group, isocyanate group, cyanate group, amino group, imino group, carbamoyl group, succinimino group, epoxy group, etc. Two are functional groups.

  The linker (B) for forming a three-dimensional structure of the present invention has at least two functional groups that bind to the functional group of the phosphazene compound (A). When the phosphazene compound (A) has two functional groups and does not form a branched structure, when the linker has two functional groups, the functional group can form a branched structure. When the functional group of the linker (B) does not form a branched structure, it is necessary to have three or more functional groups of the linker (B). However, when the phosphazene compound (A) has three or more functional groups or has a branched structure even if there are two functional groups, the linker (B) has at least two functional groups. Just do it. The linker (B) also preferably forms a reversible phase in the shape memory resin.

  The linker (B) can be appropriately selected depending on the functional group of the phosphazene compound (A). For example, when the functional group of the phosphazene compound (A) is a hydroxy group, an isocyanate group that is easily bonded to the functional group is a functional group. The preferred polyisocyanate can be mentioned.

  Specific examples of the polyisocyanate include 4,4′-diphenylmethane diisocyanate (MDI), hexamethylene diisocyanate (HMDI), trimethylhexamethylene diisocyanate (TMHMDI), toluene diisocyanate (TDI), and naphthylene diisocyanate (NDI). Lysine diisocyanate (LDI), lysine triisocyanate (LTI) and the like. In particular, amino acid-inducible LDI and LTI are natural-derived linkers and are preferable. These isocyanates may be carbodiimide-modified or isocyanurated (trimerized) (isocyanurate compound). Furthermore, an MDI having an aromatic skeleton and an isocyanurate compound having a cyclic skeleton are preferable because they have high flame retardancy.

  When a polyisocyanate compound is used as the linker (B), the amount used thereof is, for example, 0.5 to 1.5 equivalents of isocyanate group relative to the active hydrogen in the functional group of the phosphazene compound (A). It is preferable to be in the range.

  In the crosslinking of the phosphazene compound (A), the functional group of the phosphazene compound (A) is bonded via a linker to form a three-dimensional structure. The bonding part of the functional group at the cross-linked site becomes a stationary phase in the shape memory resin, and the phosphazene compound (A) between the cross-linked sites becomes a reversible phase.

  In the present invention, the shape memory resin precursor used together with the phosphazene compound (A) is not particularly limited as long as it is a resin that is usually used for production of a shape memory resin, but has excellent shape memory characteristics. What has the three-dimensional crosslinked structure by a covalent bond is desirable.

  In the present invention, since the flame retardant is highly dispersed in the shape memory resin and exhibits excellent flame retardancy and shape memory properties, the flame retardant is not mixed after the crosslinking treatment of the shape memory resin precursor. It is desirable to form the flame retardant as a crosslinked structure during the formation of the memory resin. In order to further improve the uniformity and dispersibility of the flame retardant, the functional group of the shape memory resin precursor used together with the phosphazene compound (A) may be the same as the functional group of the phosphazene compound (A). desirable. Specifically, in the case of the shape memory resin disclosed in Patent Document 1, the shape memory resin is constituted by crosslinking a precursor having a plurality of furan groups with a linker having a maleimide group. When the phosphazene compound (A) of the present invention has a plurality of furan groups and is crosslinked using the same linker, a uniform and integrated three-dimensional crosslinked structure can be obtained, and high flame retardancy and shape memory properties are obtained. Can be obtained. In the case of the shape memory resin disclosed in Patent Document 2, the shape memory resin is constituted by crosslinking a precursor having a plurality of hydroxyl groups with a linker having an isocyanate group. When the compound (A) has a plurality of hydroxyl groups and is crosslinked using the same linker, a uniform and integrated three-dimensional crosslinked structure can be obtained, and high flame retardancy and shape memory properties can be obtained. it can.

  The shape memory resin precursor used together with the phosphazene compound is preferably a plant-derived resin or a biodegradable resin in consideration of environmental characteristics. In this case, since the flame retardant of the present invention is a petroleum-derived compound, the smaller the amount added, the higher the plant-derived degree and biodegradation rate as the shape memory resin. Therefore, the addition amount of the phosphazene compound (A) is preferably 55% by weight or less, more preferably 45% by weight or less, particularly preferably 45% by weight or less, based on the total of the shape memory resin precursor, the phosphazene compound (A) and the linker (B). Preferably it is 30 weight% or less. In addition, this addition amount is determined in consideration of the above flame retardancy.

  The time required for the crosslinking of the phosphazene compound (A) in the shape memory resin varies depending on the presence or absence of the catalyst and the type of the functional group, but the phosphazene compound (A) is a polyhydroxyphosphazene compound and the linker (B) is a polyisocyanate. In some cases, the shape memory resin or a precursor thereof and a phosphazene compound can be formed by heating to a melting temperature or higher and heating and mixing with a polyisocyanate used as a linker. For example, if it is 150 degreeC, even if it does not use a catalyst, it can bridge | crosslink in about 1 hour, and if an appropriate catalyst is selected, it can fully bridge | crosslink in several minutes.

  In the present invention, a thermoplastic resin such as polypropylene, polystyrene, ABS, nylon, polyethylene terephthalate, polybutylene terephthalate, polycarbonate, urea resin, melamine resin, alkyd resin, acrylic, as long as flame retardancy and shape memory are not impaired. Resin, unsaturated polyester resin, diallyl phthalate resin, epoxy resin, silicone resin, cyanate resin, isocyanate resin, furan resin, ketone resin, xylene resin, thermosetting polyimide, thermosetting polyamide, styrylpyridine resin, nitrile It is possible to use a thermosetting resin such as a terminal resin, an addition curable quinoxaline, or an addition curable polyquinoxaline resin in combination.

  In the present invention, an organic flame retardant such as a halogen flame retardant, a nitrogen flame retardant, or a phosphorus flame retardant can be added as long as it does not affect the shape memory property. Examples of nitrogen-based flame retardants include melamine and isocyanuric acid compounds. Examples of phosphorus-based flame retardants include red phosphorus, phosphoric acid compounds, and organic phosphorus compounds.

  Similarly, an inorganic flame retardant such as metal hydrate or antimony trioxide can be added as long as it does not affect the shape memory property. Examples of such inorganic flame retardants include aluminum hydroxide, magnesium hydroxide, dosonite, calcium aluminate, hydrated gypsum, calcium hydroxide, zinc borate, barium metaborate, borax, kaolin clay, and calcium carbonate. Preferred are those whose surfaces are surface-treated with various organic substances such as epoxy resins and phenol resins, and those in which metal components are dissolved. Of these, aluminum hydroxide is particularly preferable because it has a high endothermic effect and is excellent in flame retardancy.

  Furthermore, as long as the shape memory property is not affected, high strength fibers can be used as a technique for improving impact strength. High-strength fibers include polyamide fibers such as aramid fibers and nylon fibers; polyester fibers such as polyarylate fibers and polyethylene terephthalate fibers; polyolefin fibers such as ultrahigh-strength polyethylene fibers and polypropylene fibers; carbon fibers, metal fibers, and glass fibers. Is mentioned.

  A flexible component can also be used to improve impact resistance. As the flexible component, known substances can be used, and the following substances can be exemplified. Block copolymer whose segment is polyester, polyether or polyhydroxycarboxylic acid, block copolymer whose segment is polylactic acid, aromatic polyester and polyalkylene ether, block copolymer whose segment is polylactic acid and polycaprolactone , Polymers based on unsaturated carboxylic acid alkyl ester units, polybutylene succinate, polyethylene succinate, polycabrolactone, polyethylene adipate, polypropylene adipate, polybutylene adipate, polyhexene adipate, polybutylene succinate adipate, etc. Aliphatic polyester, polyethylene glycol and its esters, polyglycerin acetate, epoxidized soybean oil, epoxidized linseed oil, epoxidized flax Oil fatty acid butyl, adipic acid based aliphatic polyester, acetyl tributyl citrate, acetyl ricinoleic acid ester, sucrose fatty acid esters, sorbitan fatty acid esters, adipic acid dialkyl esters, plasticizers such as alkyl phthalyl alkyl glycolates.

  A catalyst may be used as necessary. For example, when the reaction of a hydroxy group and an isocyanate group is performed, a tertiary amine such as triethylenediamine or an organometallic compound such as dibutyltin di (2-ethylhexoate) can be used. Triphenylphosphine, imidazole, or the like can be used for the reaction between a hydroxy group and an epoxy group.

  These compositions include foaming agents, foam stabilizers, inorganic fillers, organic fillers, reinforcing materials, colorants, stabilizers (radical scavengers, antioxidants, etc. as long as the properties such as shape memory properties of the molded products are not impaired. Agents), antibacterial agents, fungicides, flame retardants, plasticizers, mold release agents, impact resistance improvers, and the like can be included as necessary. Examples of the inorganic filler include silica, alumina, talc, sand, clay, and iron slag. Examples of the organic filler include organic fibers such as polyamide fibers and plant fibers. Examples of the reinforcing material include glass fiber, carbon fiber, polyamide fiber, polyarylate fiber, acicular inorganic material, and fibrous fluororesin. Antibacterial agents include silver ions, copper ions, zeolites containing these, and the like.

  The precursor composition of the shape memory resin composition containing various components as described above is generally used for thermosetting resins such as transfer molding, casting molding, compression molding, RIM molding, and injection molding. Depending on the molding method, it can be molded into voting paper, etc., such as electrical / electronic equipment applications such as housings of electrical appliances, building materials, automobile parts, daily necessities, medical applications, agriculture, glasses, hearing aids, gibbs, etc.

  There are no particular limitations on the method of mixing the various components of the precursor composition in the present invention, and mixing and extrusion using known mixers such as tumblers, ribbon blenders, uniaxial and biaxial kneaders, etc. And melt mixing.

  The present invention will be described in more detail with reference to the following examples, but the technical scope of the present invention is not limited thereto.

The phosphazene compound is a dihydroxyphenylphosphazene compound (X) (composition formula N ₃ P ₃ (OPh) _3.92 (OC ₆ H ₄ OH) _2.08 , hydroxyl equivalent based on the methods disclosed in Synthesis Examples 1 to 5 of Patent Document 6 350 g / mol) was synthesized.

  As the polyfunctional polylactic acid compound, hexahydroxypolylactic acid (Y) (molecular weight: 8400, hydroxyl group equivalent: 1400 g / mol) was synthesized based on Example 1 [Synthesis of terminal hydroxypolylactic acid] of Patent Document 2.

  As the linker, a commercially available trifunctional isocyanurate compound (Z) (manufactured by Asahi Kasei Chemicals Corporation, trade name: Duranate TPA-100, isocyanate equivalent: 181) was used as it was.

Example 1
12 g of the bifunctional dihydroxyphenylphosphazene compound (X) and 88 g of hexahydroxypolylactic acid (Y) are melted at 180 ° C., and 18 g of the trifunctional isocyanurate compound (Z) are quickly mixed. This was poured into a 180 ° C. mold and press-molded (2 hours) to obtain molded bodies having a thickness of 3.2 mm and 1 mm.

[Evaluation of flame retardancy]
Using a molded body having a thickness of 3.2 mm, flame retardancy was evaluated according to a vertical combustion test of UL (Underwriter Laboratories) 94 standard. The evaluation criteria for flame retardancy are as shown in Table 2.

[Evaluation of shape memory]
The shape memory property was evaluated using a molded product having a thickness of 3.2 mm.
-Deformation retention property The molded body was heated at Tg + 50 ° C, bent so that one side was lifted by 30 ° at the center of the molded body, held for 5 seconds, and then cooled and fixed to room temperature. After that, the fixation was removed, and the angle (A1) at which the lifted side was lifted from the horizontal was evaluated according to the following criteria to determine the deformation retention of the sample.
A: A1 is 20 ° or more and 30 ° or less.
Δ: A1 is 10 ° or more and less than 20 °.
X: A1 is less than 10 °.

・ Restorability The molded body whose deformation retention was measured was heated again to Tg + 50 ° C without applying pressure, then cooled to room temperature, and the lifted side lifted to the extent that the lifted angle (A1) was eliminated. The angle (A2) is measured, and evaluated according to the following criteria to be restorable.
X: A2 is 20 ° or more and 30 ° or less.
Δ: A2 is 10 ° or more and less than 20 °.
A: A2 is less than 10 °.

・ Measurement of Tg and storage elastic modulus A molded product having a thickness of 1 mm was measured with a viscoelasticity measuring device “DMS-6100” (trade name) manufactured by Seiko Instruments Inc. at a rate of temperature rise: 2 ° C./min, frequency: 10 Hz, tensile mode Then, viscoelasticity was measured, and Tg and storage elastic modulus (E ′) of 20 ° C. and (Tg + 50 ° C.) were obtained. In addition, the ratio of the storage elastic modulus at these temperatures is also an index indicating shape memory property, and when the ratio of E ′ (20 ° C.) / E ′ (Tg + 50 ° C.) exceeds 100 times, it has excellent shape memory property. I can say that.

Examples 2-6 and Comparative Examples 1-2
Except that the blending amount was changed as shown in Table 1, an evaluation molded body was prepared in the same manner as in Example 1, and the same evaluation was performed.

  Table 1 summarizes the blending ratios and evaluation results of the above comparative examples.

なお、上記の分類以外の燃焼形態をとる場合は、Ｎｏｔと分類した。ちなみに、難燃性が良好な順から悪い順に並べると、Ｖ−０、Ｖ−１、（Ｖ−２またはＮＯＴ）となる。

In addition, when taking combustion forms other than said classification, it classified as Not. By the way, if the flame retardancy is arranged in order from good to bad, V-0, V-1, and (V-2 or NOT) are obtained.

  In Comparative Example 2 and Examples 1 to 6, the hexahydroxypolylactic acid compound (Y), which is the polyol component of the shape memory resin composition shown in Comparative Example 1, was sequentially substituted with the dihydroxyphenylphosphazene compound (X). is there. Flame retardancy improves as the weight percent of (X) increases. That is, when 10% by weight or more of (X) is included, it becomes the V-1 level in the UL standard as shown in Examples 1 to 3, and when 45% by weight or more is included, the flame retardancy is further increased to the V-0 level. Was granted. In Comparative Example 2, 8% by weight of (X) was contained, but sufficient flame retardancy was not obtained. However, with respect to the shape memory property, it was confirmed that these comparative examples had deformation retention and restoration properties regardless of the substitution amount of (X).

  The precursor composition of the present invention is useful as a casing raw material for electrical / electronic equipment applications, building material applications, automotive parts applications, daily necessities applications, medical applications, agricultural applications, toys, and entertainment items.

Claims (7)

A phosphazene compound (A) having at least two functional groups and a linker (B) having two or more functional groups capable of binding to the functional groups of the phosphazene compound (A), or a shape memory resin precursor, Precursor composition of shape memory resin composition comprising phosphazene compound (A) having at least two functional groups and linker (B) having two or more functional groups capable of binding to the functional groups of the phosphazene compound (A) A thing,
The functional group of the phosphazene compound (A) is a hydroxyl group, and the functional group of the linker (B) is an isocyanate group or an epoxy group,
A shape memory resin composition in which the content of the phosphazene compound (A) is 10% by mass or more based on the total amount of the shape memory resin precursor, the phosphazene compound (A) and the linker (B) in the precursor composition. Precursor composition. The precursor composition of a shape memory resin composition according to claim 1, wherein the phosphazene compound (A) in which the functional group is a hydroxyl group is a cyclic phenylphosphazene compound. The phosphazene compound functional group is a hydroxyl group (A) is a composition formula _{N 3 P 3 (OPh) 3.92} (OC 6 H 4 OH) 2.08 is a dihydroxyphenyl phosphazene compound of claim 2 wherein the shape memory A precursor composition of a resin composition. The precursor composition of the shape memory resin composition according to any one of claims 1 to 3, wherein the linker (B) is a polyisocyanate compound having an isocyanuric group. The precursor composition of the shape memory resin composition according to claim 4, wherein the polyisocyanate compound having an isocyanuric group is a trifunctional polyisocyanate compound having an isocyanuric group. The shape memory resin composition obtained by hardening | curing the precursor composition of the shape memory resin composition of any one of Claims 1-5 . The molded object which consists of a shape memory resin composition obtained by hardening | curing the precursor composition of the shape memory resin composition of any one of Claims 1-5 .