Synthetic resins or natural rubbers -- part of the class 520 ser – Synthetic resins – Processes of preparing a desired or intentional composition...
Reexamination Certificate
2001-08-23
2004-09-14
Szekely, Peter (Department: 1714)
Synthetic resins or natural rubbers -- part of the class 520 ser
Synthetic resins
Processes of preparing a desired or intentional composition...
C524S138000
Reexamination Certificate
active
06790886
ABSTRACT:
TECHNICAL FIELD
The present invention relates to a flame-retardant resin composition comprising a polyalkylene terephthalate-series resin.
BACKGROUND ART
A polyalkylene terephthalate-series resin such as a polybutylene terephthalate has excellent mechanical and electrical properties, weather resistance, water resistance, and resistance to chemicals and solvents. Therefore fore, the resin is used as an engineering plastic in a variety of applications such as electric or electronic device parts, mechanical device parts and automotive parts. While, the resin is required to be flame-retardant from viewpoint of safety as the field of their uses expands. In general, there is known a method for rendering the resin flame-retardant by adding a flame retardant composed of a halogen-containing compound and/or an antimony-containing compound to the resin.
Japanese Patent Application Laid-Open No. 168297/1998 (JP-10-168297A) discloses a flame-retardant resin composition comprising a thermoplastic polyester resin, a polycarbonate-series resin, an organic phosphorus-series flame retardant which is a phosphate-series flame retardant. Japanese Patent Application Laid-Open No. 195283/1998 (JP-10-195283A) discloses a polyester resin composition which is rendered flame-retardant by combining a phosphate having the specific structure, a novolak-type phenol resin and the specific oxide of a metal such as iron, cobalt, nickel or copper in suitable amounts. However, the phosphate-series flame retardant does not contain a harmful halogen, but a large amount of the flame retardant is required because of their inferior flame retardancy to the halogen-containing flame retardant. Thus, a bleed out and deterioration of the mechanical properties of the resin are caused and the mechanical properties can not be improved accompanied with the flame retardancy.
Moreover, Japanese Patent Application Laid-Open No. 181268/1999 (JP-11-181268A) discloses that addition of 1.5 to 15 parts by weight of a phosphazene compound and 0.5 to 30 parts by weight of talc and/or mica to 100 parts by weight of a resin mixture containing an aromatic polycarbonate-series resin and a thermoplastic polyester-series resin in the proportion of 90/10 to 50/50 (weight ratio) renders the resin mixture flame-retardant. However, the resin composition composed of the aromatic polycarbonate has a problem of resistance to solvents, and further, the moldability is lowered because of the inferior melt-flowability upon molding.
Incidentally, Japanese Patent Application Laid-Open No. 181429/1999 (JP-11-181429) discloses that either a thermoplastic resin (e.g., polyethylene terephthalate, polybutylene terephthalate, polycarbonate) or a thermosetting resin (e.g., phenol resin) is rendered flame-retardant with use of the specific phosphazene compound (e.g., a cyclic phosphazene compound, a linear phosphazene compound, a crosslinked phosphazene compound obtained by crosslinking the cyclic and/or the linear phosphazene compound with the specific group) as a flame retardant. However, in case of rendering a polyethylene terephthalate or a polybutylene terephthalate flame-retardant, the phosphazene compound alone can not sufficiently impart the flame-retardancy to the resin.
Accordingly, it is object of the present invention to provide a resin composition having a high flame-retardancy without deteriorating the properties of polyalkylene terephthalate-series resin.
DISCLOSURE OF INVENTION
The inventors of the present invention did intensive research, and finally found that a polyalkylene terephthalate-series resin can be rendered highly flame-retardant without deteriorating mechanical properties with use of a flame retardant comprising a phenoxyphosphazene compound and a phenolic resin in combination. The present invention was accomplished based on the above findings.
That is, the flame-retardant resin composition comprises a flame retardant comprising a phosphazene compound and a phenolic resin, and a polyalkylene terephthalate-series resin (e.g., polyethylene terephthalate-series resin, polybutylene terephthalate-series resin). The phosphazene compound comprises (1) a cyclic phenoxyphosphazene compound, (2) a linear phenoxyphosphazene compound, or (3) a crosslinked phenoxyphosphazene compound which are shown below.
(1) a cyclic phenoxyphosphazene compound of the formula:
wherein m is an integer of 3 to 25, and Ph denotes a phenyl group,
(2) a linear phenoxyphosphazene compound of the formula:
wherein X
1
represents the group —N═P(OPh)
3
or the group —N═P(O)OPh; Y
1
represents the group —P(OPh)
4
or the group —P(O)(OPh)
2
; n is an integer of 3 to 10,000; and Ph has the same meaning as defined in the formula (1), and
(3) a crosslinked phenoxyphosphazene compound which is formed by crosslinking at least one phenoxyphosphazene compound selected from the group consisting of the cyclic phenoxyphosphazene compound (1) and the linear phenoxyphosphazene compound (2) with at least one crosslinking group selected from the group consisting of o-phenylene group, m-phenylene group, p-phenylene group, and a bisphenylene group shown by the formula (3a):
wherein A represents —C(CH
3
)
2
—, —SO
2
—, —S— or —O—, and a denotes 0 or 1, and
wherein the proportion of the crosslinking group in the crosslinked phenoxyphosphazene compound is, in terms of phenyl group, 0.1 to 50 mol % relative to the total phenyl groups in the phenoxyphosphazene compounds (1) and (2).
The phenolic resin may comprise a phenol-novolak resin, a phenol-aralkyl resin, a polyvinylphenolic resin or the like. The flame retardant may comprise the phosphazene compound and the phenolic resin in the proportion of the former/the latter=5/95 to 95/5 (weight ratio). The amount of the flame retardant may be 1 to 100 parts by weight relative to 100 parts by weight of the polyalkylene terephthalate-series resin. The resin composition may further comprise a nitrogen-containing flame retardant (e.g., a melamine or a derivative thereof, a melamine condensate, a cyanurate of a melamine or a derivative thereof, and a salt of a pyrophosphoric acid or a polyphosphorus acid with a triazine derivative), a phosphate-series flame retardant (e.g., a phosphate, polyphosphate), a carbonizable resin (e.g., a polycarbonate-series resin, a polyarylate-series resin, an aromatic epoxy resin, a polyphenylene oxide-series resin, a polyphenylene sulfide-series resin), an antioxidant, a thermal stabilizer, a drip inhibitor a filler, and the like.
The flame-retardant resin composition can be prepared by mixing a polyalkylene terephthalate-series resin and the flame retardant.
The present invention also includes a molded article formed with the flame-retardant resin composition.
BEST MODE FOR CARRYING OUT THE INVENTION
Polyalkylene Terephthalate-series Resin
The polyalkylene terephthalate-series resin includes a homopolyester or a copolyester containing an alkylene terephthalate as a main component (e.g., about 50 to 100% by weight, preferably about 75 to 100% by weight) The homopolyester includes, for example, polyl, 4-cyclohexane dimethylene terephthalate (PCT), polyethylene terephthalate (PET), polypropylene terephthalate (PPT), polybutylene terephthalate (PBT). A copolymerizable monomer of the copolyester includes, for example, an alcohol component such as (poly)ethylene glycol, (poly)propylene glycol and (poly)butylene glycol, a carboxylic acid component such as adipic acid, sebacic acid, isophthalic acid, naphthalene dicarboxylic acid, biphenylene dicarboxylic acid, hydroxycarboxylic acid, and hydroxynaphthoic acid. These polyalkylene terephthalate can be used singly or in combination. The preferred polyalkylene terephthalate-series resin is polyethylene terephthalate-series resin, polypropylene terephthalate-series resin, and polybutylene terephthalate-series resin, and in particular, a polyC
2-4
alkylene terephthalate such as polyethylene terephthalate and polybutylene terephthalate is preferred.
The number average molecular weight of the polyalkylene terephthalate-series resin is not particularly limited,
Harashina Hatsuhiko
Nakane Toshio
Tada Yuji
Yamada Shin-ya
Nixon & Vanderhye PC
Polyplastics Co. Ltd.
Szekely Peter
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