JP3100765B2 - Resin composition - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

FIELD OF THE INVENTION The present invention relates to a flame-retardant polybutylene te
(Hereinafter abbreviated as PBT resin) Les phthalate resins relate. More specifically, a flame-retardant resin composition having excellent flame retardancy and well-balanced physical properties, having extremely low decomposition gas generated during molding and use, and having low metal contamination and high reliability. To provide.

[0002]

2. Description of the Related Art Conventionally, PBT resin as a crystalline thermoplastic resin has excellent mechanical properties, electrical properties, and other physical and chemical properties for use in electrical parts such as relays and switches. Used for In general, for applications requiring flame retardancy, such as electric parts, an organic halogen-based flame retardant, preferably one further blended with a flame retardant auxiliary to impart flame retardancy is used.

[0003] However, the PBT resin has various problems which have been pointed out so far. That is, since these resins have difficulty in hydrolysis resistance, the main PBT resin is easily decomposed and deteriorated during molding and when used as an electric component. In addition, a large amount of a flame retardant and a flame retardant aid are added to impart flame retardancy, and not only these decomposed products are generated but also the decomposition of other additives and PBT itself is promoted. Therefore, the molds are corroded and contaminated by the decomposed products at the time of molding, and the dimensional accuracy and processing efficiency of the molded products are degraded. Harmed.

[0004] The present invention is suitable for applications requiring low gas generation. Of course, the present invention is not limited to this application, but as a typical component, its value is extremely large when used in a case or bobbin of a relay component having metal electrical contacts. Contacting parts of seal type relays and switches confine gas generated from the internal constituent resin inside, and when used in a high-temperature atmosphere, there may be a problem caused by this gas. This problem is roughly divided into 2
There are different types, one is a contact opening and closing product such as black powder and the other is the corrosion of the contact metal.

In order to solve these problems, heat resistance has been sought for flame retardants, flame retardant auxiliaries, and other inorganic substances.
Screening has been carried out, and the generation of decomposition gas from molded articles and the like has been reduced to a considerable level with respect to required characteristics. However, the reduction of decomposition gas from the PBT polymer itself has not yet been fundamentally solved. Not.

[0006] In order to improve the melting heat stability of PBT, conventionally, a combination of a radical generation inhibitor such as a hindered phenol compound and a peroxide decomposed product such as a phosphorus compound or a carboxyl group such as an epoxy group or an isocyanate group has been used. A method has been proposed in which a compound having a functional group that reacts with a group is added to PBT.

However, since the above-mentioned compound has a low molecular weight, not only does the low-molecular compound bleed out on the surface of the molded product at the time of molding and use, but the compound itself is detected as a volatile gas. In particular, phenol compounds and phosphorus compounds have been reported in many experimental reports that significantly increase the electrical resistance of metal electrical contacts.

[0008] On the other hand, many modifications relating to PBT polymers relate to the improvement of hydrolysis resistance, which is the greatest drawback of polyester, and there is no report on heat stability, especially volatile gas.

The inventors of the present invention have conducted intensive studies on the improvement of the characteristics in order to further improve the characteristics, and as a result, have reached the present invention.

[0010]

According to the present invention, a brominated flame retardant of 0 to 25 is used for all PBT and polyester resin compositions having a terminal hydroxyl group concentration of 30 equivalents / ton or less (ton represents 10 ⁶ g). % By weight, 0 to 15% by weight of a flame retardant auxiliary containing antimony trioxide and / or antimony pentoxide as a main component with respect to the total composition, and 0 to 7 with respect to the total composition
0% by weight, 0.01-1.0% by weight relative to the total composition
Lithium hydroxide, sodium hydroxide, potassium hydroxide,
Rubidium hydroxide, Cesium hydroxide, Francium hydroxide
, Beryllium hydroxide, magnesium hydroxide, sodium hydroxide
Trontium, barium hydroxide, lithium acetate, sodium acetate
Thorium, potassium acetate, magnesium acetate, calcium acetate
Cium, lithium carbonate, sodium carbonate, potassium carbonate
System, lithium benzoate, sodium benzoate and benzoate
At least one member selected from the group consisting of potassium perfume
A resin composition comprising a compound and a molded article obtained by molding the composition.

The present invention will be described. In the present invention, PB
T is a polyester containing terephthalic acid as a main acid component and 1,4-butanediol as a main glycol component.

The term "principal" as used herein means that terephthalic acid or 1,4-butanediol accounts for at least 80 mol% of all acid components or all glycol components.

The acid components which can be copolymerized include aromatic dicarboxylic acids other than terephthalic acid, for example, isophthalic acid, naphthalenedicarboxylic acid, diphenyldicarboxylic acid, diphenyletherdicarboxylic acid, diphenoxyethanedicarboxylic acid, diphenylketonedicarboxylic acid, diphenylsulfonedicarboxylic acid. Examples thereof include acids, aliphatic dicarboxylic acids such as succinic acid, adipic acid and sebacic acid, and alicyclic dicarboxylic acids such as cyclohexanedicarboxylic acid, tetralindicarboxylic acid and decalindicarboxylic acid.

The copolymerizable glycol components other than butanediol include ethylene glycol, propylene glycol, pentamethylene glycol, hexamethylene glycol, octamethylene glycol, neopentyl glycol, cyclohexanedimethanol, xylylene glycol, diethylene glycol, and polyethylene. Examples thereof include glycol, bisphenol A, catechol, resorcinol, hydroquinone, dihydroxydiphenyl, dihydroxydiphenylether, dihydroxydiphenylmethane, dihydroxydiphenylketone, dihydroxydiphenylsulfide, and dihydroxydiphenylsulfone.

Examples of the oxycarboxylic acid component include oxybenzoic acid, hydroxynaphthoic acid, hydroxydiphenylcarboxylic acid, and ω-hydroxycaproic acid.

Further, a compound having three or more functions, for example, glycerin, trimethylpropane, pentaerucyltol, trimellitic acid, pyromellitic acid, etc. may be copolymerized within a range where the polyester does not substantially lose the molding performance.

The PBT used in the present invention must have a terminal hydroxyl group concentration of 30 equivalents / ton or less. Preferably it is 20 equivalents / ton or less. That is,
Tetrahydrofuran (hereinafter abbreviated as THF), which is the main gas generated from PBT, tends to be generated during melting when the terminal hydroxyl group concentration is 30 equivalents / ton or more.

Regarding this THF generation route, the first embodiment
Extruded pellets, molding temperatures 270 and 290 ° C. and 1 / 80-inch thick molded products of Comparative Examples 1 to 4 were examined for changes in melt viscosity, intrinsic viscosity, and terminal groups. Ring closure reaction formula (I) of terminal hydroxyl group

[0019]

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The ester cleavage reaction formula (II) which reduces the molecular weight

[0021]

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From this, it can be inferred that a path is not generated. Therefore, it can be said that the amount of THF significantly increases when the number of terminal hydroxyl groups is large.

The terminal hydroxyl group concentration is calculated from the total number of terminals by C
1 ton of polymer (10
It is the number of equivalents per ⁶ g). Here, the COOH group is determined by the method of A. Conix (Macromol. Ch.
em., vol. 26, page 226 (1985)}.
The total number of terminals is calculated from the intrinsic viscosity.

Alkali metal compound used in the present invention
And / or the alkaline earth metal compound contributes to stabilization of terminal OH groups by one kind of buffer effect.

[0025]

[0026]

Lithium hydroxide, sodium hydroxide, hydroxyl
Potassium chloride, rubidium hydroxide, cesium hydroxide, hydroxyl
Francium, beryllium hydroxide, magnesium hydroxide
System, strontium hydroxide, barium hydroxide, lithium acetate
, Sodium acetate, potassium acetate, magnesium acetate
, Calcium acetate, lithium carbonate, sodium carbonate,
Potassium carbonate, lithium benzoate, sodium benzoate
And at least one selected from the group consisting of potassium benzoate
In both cases, the amount of addition of one compound is 0.01 to
It is 1.0% by weight, but preferably 0.01 to 0.5% by weight. In this hereinafter effect it is not sufficiently expressed, in the case of excess, or the resulting resin composition is colored,
It is not preferred because it has side effects during compounding.

The brominated flame retardant used in the present invention is, for example, a brominated bisphenol A type polycarbonate flame retardant having a bromine content of 20% by weight or more, and a brominated bisphenol A.
Type epoxy resin and / or a modified product obtained by blocking part or all of the terminal glycidyl group, a brominated diphenyl ether flame retardant, a brominated imide flame retardant, a brominated polystyrene flame retardant, and the like. These flame retardants are present in the composition at 0-2.
It is added in an amount of 5% by weight, preferably 2 to 15% by weight.

The antimony-based flame retardant auxiliary used in the present invention preferably has a particle size of 0.02 to 5 μm. If necessary, the surface may be treated with an epoxy compound, a silane compound, an isocyanate compound, a titanate compound, or the like. The addition amount of the flame retardant aid is 0 to 15 with respect to the total composition.
%, Preferably 1 to 10% by weight.

The preparation of the composition of the present invention is easily adjusted by known equipment and methods generally used as a conventional method for preparing a resin composition. For example, after mixing each component, melt kneading and extruding with an extruder to adjust the pellets,
Thereafter, a method of molding, a method of once preparing pellets having different compositions, mixing the pellets in a predetermined amount and subjecting the mixture to molding to obtain a molded article of a desired composition after molding, and directly charging one or more of each component to a molding machine Any method can be used. Mixing and adding a part of the resin component as a fine powder with other components is a preferable method for uniformly blending these components.

If desired, other additives such as a coloring agent, an ultraviolet absorber, and the like may be added to the resin composition provided for the electric component of the present invention.
Release agents, antistatic agents, crystallization promoters, sulfur stabilizers, fillers, impact modifiers, and the like can be added.

[0032]

Next, the present invention will be further described with reference to examples.
Polybutylene terephthalate used in Examples
Rimmer, phenolic stabilizer, release agent, glass fiber, B
The r-epoxy and the release agent are as follows. (1) Polybutylene terephthalate polymer: dimethyl terephthalate and tetramethylene
Recalls titanium tetrabutoxide as catalyst
After the transesterification reaction using, the temperature was increased under reduced pressure,
Tables 1 and 2 were obtained by adding potassium iodide and polymerizing.
Polybutylene tele having the stated IV and end group concentrations
Phthalate polymer. (2) a phenolic stabilizer (antioxidant): IRGANOX 1010 (manufactured by Nippon Ciba-Geigy Co., Ltd.) (3) mold release agent: (manufactured by Hoechst Japan (Ltd.)) Wax-E (4) glass fiber: 10.5μm diameter, 3mm chopped strand (Nippon Electric Glass
( 5) Br-epoxy: F-2300H (Dead Sea Bromin, Israel )
Company Ltd.) (6) antimony pentoxide: partially neutralized product of sodium antimonate: San Epoch N
A1030 (manufactured by Nissan Chemical Industries, Ltd.) The measuring method of the characteristic evaluation shown in the examples is as follows.

1) Flame retardancy test (UL-94) Subject 9 of Underwriters Laboratories
5 (UL-94) 5 specimens (thickness: 1
/ 32 inches).

2) Method for evaluating metal contamination After the sample (pellet) was sufficiently dried, 50 g of pellet was obtained.
Was sealed in a glass container together with a silver plate (15 mm × 20 mm × 0.2 mm) and heated at 200 ° C. for 200 hours to observe the discoloration of the silver plate.

3) Decomposed gas (volatile gas) A 10 g pellet sample was collected in a 27 ml (S. headspace) container (27 ml). Heat treatment is performed at 150 ° C. for 60 minutes with an S heater. The generated gas is quantitatively analyzed by gas chromatography.

[0036]

Examples 1-4 and Comparative Examples 1-4 Intrinsic viscosities (abbreviated as IV: measured in orthochlorophenol at 35 ° C.), terminal OH groups and COOH groups for PBT polymers are as described in the table. .

The components were mixed according to the composition shown in Table 1, melted and extruded by an extruder.

The measurement of THF was carried out using extruded pellets, a molding temperature of 270.degree.
A 1/80 inch Achi difference crushed test piece injection molded at 0 ° C was used.

[0039]

[Table 1]

[0040]

Examples 5 to 8 and Comparative Examples 5 to 6 In order to impart flame retardancy, 10% glass fiber, 17% Br-epoxy, 9% antimony pentoxide, Extrusion was performed by adding 0.4% of a release agent, 0.2% of an antioxidant, and 0.02% of potassium acetate.

The measurement of THF was performed in Examples 1 to 4 (Comparative Example 1).
4) The same method as that used in 4) was used.

[0042]

[Table 2]

Continuation of front page (58) Field surveyed (Int.Cl. ⁷ , DB name) C08G 63/183 C08L 67/02

Claims (3)

(57) [Claims] 1. A polybutylene terephthalate having a terminal hydroxyl group concentration of 30 equivalents / ton or less, 0.01 to the total composition.
~ 1.0 wt% lithium hydroxide, sodium hydroxide,
Potassium hydroxide, rubidium hydroxide, cesium hydroxide,
Francium hydroxide, beryllium hydroxide, magnesia hydroxide
Cium, strontium hydroxide, barium hydroxide, acetic acid
Lithium, sodium acetate, potassium acetate, magne acetate
Cium, calcium acetate, lithium carbonate, sodium carbonate
, Potassium carbonate, lithium benzoate, sodium benzoate
Selected from the group consisting of potassium and potassium benzoate.
At least one compound, no brominated flame retardant for the entire composition
-25% by weight, based on the total composition, a flame retardant aid containing antimony trioxide and / or antimony pentoxide as a main component.
15% by weight, and 0 to 70 inorganic fillers for the total composition
A resin composition consisting of% by weight. 2. Polybutylene terephthalate having a terminal hydroxyl group concentration of 30 equivalents / ton or less, 2 to 15% by weight of a brominated flame retardant based on the total composition, and antimony trioxide and / or antimony pentoxide based on the total composition. 1 to 10% by weight of a flame retardant aid as a component, 5 to 60 inorganic fillers based on the total composition
% By weight, 0.01 to 1.0% by weight of hydroxyl based on the total composition
Lithium chloride, sodium hydroxide, potassium hydroxide, hydroxyl
Rubidium fluoride, cesium hydroxide, francium hydroxide,
Beryllium hydroxide, magnesium hydroxide, hydroxide hydroxide
Sodium, barium hydroxide, lithium acetate, sodium acetate
, Potassium acetate, magnesium acetate, calcium acetate
, Lithium carbonate, sodium carbonate, potassium carbonate,
Lithium benzoate, sodium benzoate and potassium benzoate
A resin composition comprising at least one compound selected from the group consisting of lithium. 3. A molded article obtained by molding the resin composition according to claim 1 or 2.