JPH04345655A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To provide the title compsn. which is excellent in moldability, does not stain nor corrode a metal mold, and gives a molding with a high dimensional accuracy. CONSTITUTION:The title compsn. which is suitable for an electric part, etc., comprises a polybutylene terephthalate resin, a flame retardant consisting of a brominated epoxy or polycarbonate resin, an auxiliary flame retardant consisting of antimony tri- or pentaoxide, an ethylene-ethyl acrylate copolymer, and, if necessary, a hydrated Mg-Al carbonate and an inorg. filler.

Description

[Detailed description of the invention]

0001

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a flame-retardant resin composition based on polybutylene terephthalate. More specifically, it has excellent flame retardancy and well-balanced performance,
The moldability (fluidity, molding cycle, mold contamination, mold corrosion, etc.) has been greatly improved, and metal contamination and volatile gas and volatile substance generation when used in electrical parts etc. have been significantly improved. The purpose of the present invention is to provide a resin composition which has a well-balanced improvement in mechanical properties, heat resistance, etc. as well as greatly improving the surface appearance of molded products.

0002

[Prior art and its problems] Polybutylene terephthalate homopolymers or copolymers containing at least 60% by weight of butylene terephthalate monomers and/or thermoplastic polyester mixtures containing at least 60% by weight of polybutylene terephthalate (hereinafter collectively referred to as (abbreviated as PBT) is a crystalline thermoplastic resin with excellent mechanical properties, electrical properties, and other physical and chemical properties, so it is used as an engineering plastic for automobiles, electrical equipment,
It is used in a wide range of applications such as electronic equipment.

[0003] Conventionally, organic halogen flame retardants have been mainly used for applications such as electrical parts that require flame retardancy, and if necessary, flame retardant additives have been added to impart flame retardancy. ing.

However, conventional PBT resin compositions containing flame retardants and flame retardant aids have the following problems. ■The physical properties of molded products deteriorate due to the presence of flame retardants and additives. (2) Due to flame retardants, co-used auxiliaries, or their interactions, PBT, which is the base material, decomposes and deteriorates during composition preparation, molding, or when molded products are used in high-temperature atmospheres. ■
Flame retardants, co-used auxiliary agents, or their decomposition byproducts generate volatile gases that corrode and contaminate molds, deteriorating the dimensional accuracy and processing efficiency of molded products. ■Flame retardants, co-auxiliary agents, their decomposition by-products, and decomposition products of PBT as mentioned in ■ above may cause spots on the molded product or may adhere to other nearby parts.
Discolors and impairs appearance and performance. (2) Due to poor compatibility between the flame retardant and the resin, the flame retardant oozes out onto the surface of the molded product, causing various problems. ■The fluidity of the resin is inhibited, causing problems in molding. - When using molded products, the decomposition products of flame retardants and additives will corrode or contaminate adhesives or nearby metals, impairing the functionality of parts. For example, when used in electrical parts having metal electrical contacts (for example, housings and circuit boards for switches, relays, etc.), the contact metals become contaminated during long-term use, and the electrical resistance of the contacts increases significantly.

Improvements have been proposed for each of these problems. However, even if some of these problems are satisfied, it is extremely difficult to obtain a flame-retardant PBT composition that improves all of the above problems, and its realization has been eagerly awaited.

[0006] In general, PBT is relatively easier to mold than polyethylene terephthalate, but in recent years, as molded products have become more complex in shape, smaller, and thinner, it has become necessary to use resins with higher fluidity and to reduce the manufacturing cost of molded products. In many cases, it is desired to do so, and there is an increasing demand for improving productivity by shortening the molding cycle (or high-cycle molding).

[0007]

[Means for Solving the Problems] The present inventors have achieved excellent flame retardancy, as well as excellent, well-balanced functions without any drawbacks as described above, and in particular, the fluidity has been greatly improved. ,
At the same time, it is possible to obtain a PBT resin composition that can shorten the molding cycle, enable high-cycle molding, extremely suppress the generation of volatile gases and volatile substances due to metal contamination in high-temperature atmospheres, and improve the surface appearance of molded products. As a result of careful consideration,
We have arrived at the present invention.

That is, the present invention provides (A) polybutylene terephthalate and/or a copolymer containing 60.0 wt% or more of a butylene terephthalate monomer, and/or a thermoplastic polyester containing 60.0 wt% or more of polybutylene terephthalate. mixture, (B) brominated epoxy resin flame retardant and/or brominated polycarbonate flame retardant 2.0 to 25.0 wt% (in total composition), (C) mainly antimony trioxide and/or antimony pentoxide 2.0 to 15.0 wt% of flame retardant aid as a component (in the whole composition), (
D) Ethylene-ethyl acrylate copolymer 2.0-2
0.0wt% (in total composition), (E) hydrated basic carbonate compound of magnesium and aluminum 0 to 10.0w
t% (in total composition), and (F) inorganic filler 0-70
．． It is a flame retardant resin composition consisting of 0 wt% (of the entire composition).

The constituent components of the resin composition of the present invention will be explained in detail below.

First, the PBT resin (A) used in the present invention is polybutylene terephthalate obtained by polycondensing 1,4-butanediol and terephthalic acid or its lower alcohol ester. A copolymer containing 60% by weight or more may be used. Monomers to be copolymerized include isophthalic acid,
aliphatic and aromatic polybasic acids such as naphthalene dicarboxylic acid, adipic acid, sebacic acid, trimellitic acid, and succinic acid;
or ester-forming derivatives thereof, aromatic hydroxycarboxylic acids such as hydroxybenzoic acid and hydroxynaphthoic acid, or ester-forming derivatives thereof, 1,3-propanediol, 1,6-hexanediol, 1,8-octanediol, etc. Lower alkylene glycol, bisphenol A, aromatic alcohol such as 4,4'-dihydroxybiphenyl, 2 mole ethylene oxide adduct of bisphenol A, propylene oxide 2 of bisphenol A
Examples include alkylene oxide adducts such as molar adducts, alcohols, polyhydroxy compounds such as glycerin and pentaerythritol, and ester-forming derivatives thereof.

Furthermore, it may be a thermoplastic mixture containing 60% by weight or more of polybutylene terephthalate, and a thermoplastic polyester consisting of the above acid component, glycol component, and oxycarboxylic acid component may be used as long as the physical properties are not significantly impaired. It is possible to mix. Examples of the thermoplastic polyester include polyethylene terephthalate, polyethylene isophthalate, polyethylene naphthalate, polybutylene naphthalate, polycyclohexanedimethanol terephthalate, and the like.

Particularly preferred are polybutylene terephthalate homopolymers.

Next, the content of component (B) used in the present invention is 2 to 25% by weight, preferably 5 to 20% by weight, based on the total amount of the composition. If the amount is too large, the mechanical, physical properties, thermal stability, etc. will be impaired, and the appearance and moldability of the resin will be impaired, which is not preferable. Moreover, if the amount is too small, not only will flame retardance be insufficient, but also thermal stability and moldability will be impaired.

Next, the amount of the flame retardant aid (C) containing antimony trioxide and/or antimony pentoxide as a main component used in the present invention is 2 to 15% by weight based on the total amount of the composition, preferably It is 3 to 10% by weight. If the amount is too large, the decomposition of the resin and compounding agents will be promoted, and if it is too small, the flame retardance will be insufficient. A flame retardant aid containing antimony pentoxide as a main component is represented by general formula (III). (Na2O)p ・Sb2O5 ・q
H2O(III) (p is 0.4~
0.9, and q is crystal water and represents a numerical value of 0 to 4. )

When a brominated epoxy flame retardant is used as the flame retardant (B) component, an auxiliary agent containing antimony trioxide and/or antimony pentoxide of the above formula (III) as a main component may be used as a concomitant auxiliary agent. However, if a brominated polycarbonate flame retardant is used, it is preferable to use antimony trioxide. When the auxiliary agent of formula (III) is used, the decomposition of the carbonate group is likely to be accelerated, and the resin composition decomposes and foams, impairing its mechanical and physical properties, thermal stability, and the like.

The ethylene-ethyl acrylate copolymer of component (D) preferably has an ethyl acrylate content of 10 to 50%. (D) in the flame retardant resin composition of the present invention
The amount of the component used is 2 to 20 wt%, preferably 2 to 1
It is 0wt%. If it is less than 2wt%, volatile gases (especially TH
The effect of reducing generation of F (F amount) and improving fluidity is small, and if it exceeds 20 wt%, it causes a decrease in strength, which is not preferable.

Component (E) has the formula Mg6Al2, for example.
(OH)16CO3 ・4H2 O, or Mg4.2
Al2 (OH)12.4CO3 ・kH2 O or M
g4.5 Al2 (OH)13CO3 ・3.5 H
It is a natural or synthetic hydrotalcite compound represented by 2 O. Therefore, it can be represented by the following general formula (V). Mg1-h Alh (OH)2 (CO
3) h/z ・kH2O (V) (However, h is 0.2 to 0.4, and k is crystal water and indicates a value of 2 or less.)

The content of component (E) is 0 to 1 in the total amount of the composition.
The amount is 0.0% by weight, preferably 0 to 7.0% by weight. Excessive amounts will promote the decomposition of PBT and flame retardants,
If the amount is too small, the effect of inhibiting decomposition will be insufficient.

Next, the inorganic filler (F) used in the present invention
are mechanical strength, heat resistance, dimensional stability (deformation resistance, warping),
It is preferable to blend them in order to obtain a molded product with excellent performance such as electrical properties, and fillers in the form of fibers, particles, or plates are used depending on the purpose.

Examples of fibrous fillers include glass fiber, carbon fiber, silica fiber, sicari/alumina fiber, zirconia fiber, boron nitride fiber, silicon nitride fiber, boron fiber, potassium titanate fiber, stainless steel, aluminum, titanium, Examples include inorganic fibrous materials such as fibrous materials of metals such as copper and brass. Particularly typical fibrous fillers are glass fibers or carbon fibers. Note that high melting point organic fibrous substances such as polyamide and acrylic resin can also be used.

On the other hand, the powdery fillers include carbon black, silica, quartz powder, glass beads, glass powder, calcium silicate, aluminum silicate, kaolin, talc,
Silicates such as clay, diatomaceous earth, wollastonite, metal oxides such as iron oxide, titanium oxide, zinc oxide, alumina, metal carbonates such as calcium carbonate, calcium carbonate, calcium sulfate, barium sulfate. Examples include sulfates of metals such as silicon carbide, silicon nitride, boron nitride, and various metal powders.

[0022] Examples of the plate-shaped filler include mica, glass flakes, and various metal foils.

These inorganic fillers may be used alone or in combination of two or more. The combined use of fibrous fillers, particularly glass fibers, and granular and/or plate-like fillers is a preferred combination in terms of mechanical strength, dimensional accuracy, electrical properties, and the like.

When using these fillers, it is desirable to use a sizing agent or a surface treatment agent if necessary. Examples of this include functional compounds such as epoxy compounds, isocyanate compounds, silane compounds, and titanate compounds. These compounds may be used after surface treatment or convergence treatment, or may be added at the same time when preparing the material.

In the present invention, the amount of the inorganic filler blended is 0 to 70% by weight, preferably 5 to 70% by weight based on the total amount of the composition.
It is 60% by weight. If the amount of the inorganic filler exceeds 70% by weight, not only will molding become difficult, but also problems will arise in the mechanical strength of the molded product. The amount of the functional surface treatment agent used in combination is 1 to 10% by weight, preferably 0.05 to 5% by weight, based on the inorganic filler.

[0026] The features of the present invention are (A) PBT;
, (B) brominated epoxy flame retardant and/or brominated polycarbonate flame retardant, (C) antimony trioxide and/
or a flame retardant aid containing antimony pentoxide as a main component and (D
) This is due to the synergistic effect of the combination of the four components of the ethylene-ethyl acrylate copolymer, and if any one of these four components is absent or replaced with another substance, the effect of the present invention will not be achieved. I can't get it.

That is, by using the flame retardant as the component (B) and the flame retardant aid as the component (C) of the present invention, PB
Although it is possible to impart flame retardancy to T-resin, this alone causes decomposition of PBT and organic compounding agents, generating volatile gases and volatile substances, leading to metal corrosion or contamination of molded electrical parts, etc., and molds of molded products. corrosion or contamination. As a result of our earnest efforts, we discovered that by further blending component (D) with these, we could not only extremely suppress the amount of volatile gases and volatile substances generated, but also greatly improve fluidity.

Even when used as is, the composition of the present invention has excellent low volatile gas properties, high fluidity, and mechanical properties as a flame retardant resin composition compared to conventionally known flame retardant-containing resin compositions. It has high thermal stability and also has a remarkable effect on molding cycle metal contamination.
Further effects can be obtained by using (E) a hydrous basic carbonate compound of magnesium and aluminum in combination with components A) to (D).

The composition of the present invention may further contain known additives, such as lubricants, nucleating agents, mold release agents, antistatic agents, and other surface active agents in addition to the above-mentioned components, in order to impart desired properties depending on its purpose. Of course, it is also possible to add additives, plasticizers, colorants, heat stabilizers, ultraviolet stabilizers, and the like.

The composition of the present invention can be easily prepared using known equipment and methods commonly used for conventional resin composition preparation methods. For example, i) a method in which each component is mixed and then kneaded and extruded using an extruder to prepare pellets, and then molded; ii) pellets with different compositions are once prepared, a predetermined amount of the pellets are mixed, and molding is performed. Any method can be used, such as a method of obtaining a molded article having the desired composition after molding, and iii) a method of directly charging one or more of the components into a molding machine. Further, mixing with the resin component and adding it is a preferable method for uniformly blending these components.

[0031]

[Examples] The present invention will be specifically explained below with reference to Examples.

The measurement method for evaluating the characteristics shown in the Examples is as follows.

(1) Physical property measurement method tensile test ASTM D 63
Compliant with 8, Izod impact strength ASTM D 25
Compliant with 6.

(2) Retention test in the molding machine (thermal stability) The sample was retained in the cylinder of the molding machine for 30 minutes at a cylinder temperature of 260°C, then molded, and the tensile test of the molded test piece was measured to determine the thermal stability. The quality and degree of deterioration were evaluated.

(3) Flammability test (UL-94) Underwriters Laboratories Subject 94 (UL-94)
According to the method of UL-94), five test pieces (thickness: 1
/32 inches) for flame retardancy.

(4) Flowability measurement method Test mold for rod flow length measurement (cavity: width 20mm x
Molding was performed under the following conditions using a molded material (thickness: 2.0 mm), and fluidity was evaluated from the flow length (molded product length). Molding conditions Cylinder temperature: 250℃ injection pressure
:1000kg/cm2 Mold temperature
:60℃

(5) Limit molding cycle A cylindrical bottomed molded product (outer diameter 40mmφ, height 40mm, average wall thickness 5mm) was molded under the following conditions, and the molded product did not lose its shape and had a good appearance. The limit time (seconds) required for the molding cycle that could yield the product was determined. The lower the value, the better the high cycle moldability. Molding conditions Cylinder temperature: 250℃ injection pressure
:1400kg/cm2 Mold temperature
: 90°C Molding cycle: The cooling time was determined by keeping the injection holding pressure constant.

(6) Molded Product Appearance Inspection A disk (100 mm diameter, 3 mm thickness) was molded, and the presence and extent of unusual colored spots were visually observed and judged according to the following ranks. Spots ○: None △: Slightly present ×: Many spots present

(7) Evaluation method for metal contamination After thoroughly drying the sample (pellet), 50 g of the pellet was placed on a silver piece (15 m
m x 2 mm x 0.2 mm) and sealed in a glass tube.
After heating at 00°C for 200 hours, the state of discoloration of the silver piece was observed. Discoloration ○: None △: Slight discoloration ×: Severe discoloration

(8) Evaluation of resin decomposition products under high temperature atmosphere A molded piece (40 mm x 13 mm x 0.9 mm) was sealed in a glass tube and then heat treated at 170°C for 25 days, and the amount of decomposed products generated was observed and compared. did.

(9) Evaluation of bromine generation amount A cylindrical glass container is placed in a flow path of heated air at 300°C, filled with resin, and immersed in an oil bath at 300°C. The circulating air is introduced into pure water, and the generated bromine is collected as HBr for 1 hour. This aqueous solution was analyzed using an ion chromatograph to determine the weight of HBr generated (ppm) relative to the encapsulating resin.
) to measure.

(10) Evaluation of amount of THF generated by HS-GC Using HS-GC at a column temperature of 200° C., the weight of THF generated (ppm) is measured.

[0043]

[Examples 1 to 7, Comparative Examples 1 to 16] After adding and mixing the various components shown in Table 1 to PBT and a brominated epoxy flame retardant and/or a brominated polycarbonate flame retardant, pellets were produced using an extruder. A composition was prepared. Next, the pellets were injection molded to prepare various test pieces, and the evaluations described above were performed. The results are shown in Table 1. As PBT, a homopolymer having an intrinsic viscosity of 0.88 was used.

Further, the hydrotalcite compound is Mg0.68Al0.3 with x=0.32 and m=0 in claim 5.
2(OH)2(CO3)0.16 was used.

[0045]

[Examples 8 to 15, Comparative Examples 17 to 33] After adding and mixing the various components shown in Table 2 to the PBT homopolymer, copolymer, or mixture, Examples 1 to 7 and Comparative Examples 1 to 8 were prepared. Evaluations were made in the same manner, and the results are shown in Table 2.

[0046] The PBT copolymer contains 7% by weight (based on the total polymer amount) of ethylene glycol (EG) and PBT copolymer.
A copolymer containing 30% polyethylene glycol (PET) and 70% PBT was obtained by copolymerizing using a conventional synthesis method and used. In addition, 10% by weight of EG was copolymerized,
Similarly, a copolymer containing 44% PET and 56% PBT was obtained and used.

On the other hand, the PBT mixture consists of PBT with an intrinsic viscosity of 0.88 and polyethylene terephthalate (PE) with an intrinsic viscosity of 0.70.
T) in a predetermined ratio.

[0048]

Effects of the Invention As is clear from the above description and examples, brominated epoxy flame retardant and/or brominated polycarbonate diameter flame retardant, some sodium salt of antimony pentoxide and/or antimony trioxide and ethylene ethyl The resin composition of the present invention containing an acrylate copolymer has the following properties effectively improved and has excellent, well-balanced functions. ■During molding, no deposits are observed on the mold surface, and because it has excellent thermal stability, there is less mold corrosion due to decomposition products, etc., and processing efficiency is improved. ■Less thermal deterioration of molded products. ■No abnormal color spots are observed on the molded product. ■It has excellent flame retardancy, and no flame retardant seeps out during use. ■Excellent mechanical properties such as tensile properties and Izod impact strength. ■Excellent fluidity,
The solidification speed is fast, the molding cycle is shortened, and high-cycle molding is possible. ■Metals that coexist during use (contacts)
Corrosion or contamination can be effectively improved. ■The amount of volatile gas generated by resin decomposition products in a high-temperature sealed atmosphere is reduced, and adhesion to other nearby parts and contamination and discoloration are suppressed.

The resin composition of the present invention can be used for electrical and electronic parts such as relays, connectors, switches, and transformer coil bobbins.

[0050]

[Table 1]

[0051]

[Table 2]

[0052]

[Table 3]

[0053]

[Table 4]

[0054]

[Table 5]

[0055]

[Table 6]

Claims (1)

[Scope of Claims] [Claim 1] (A) polybutylene terephthalate and/or
or 60.0 wt% butylene terephthalate monomer
copolymer containing the above, and/or thermoplastic polyester mixture containing 60.0 wt% or more of polybutylene terephthalate, (B) brominated epoxy resin flame retardant and/or brominated polycarbonate flame retardant 2.0 to 25 ．．
0 wt% (in total composition), (C) flame retardant auxiliary agent mainly composed of antimony trioxide and/or antimony pentoxide 2.0
~15.0 wt% (in total composition), (D) ethylene-ethyl acrylate copolymer 2.0 to 20.0 wt% (in total composition), (E) Hydrous basic carbonate of magnesium and aluminum A flame-retardant resin composition comprising 0 to 10.0 wt% of a compound (in the total composition) and 0 to 70.0 wt% of an inorganic filler (F) (in the total composition). [Claim 2] The brominated epoxy flame retardant of component (B) is a brominated bisphenol A type epoxy resin represented by the following general formula (I) with a bromine content of 20% by weight or more and/or a part of its terminal glycidyl group. The flame-retardant resin composition according to claim 1, comprising a modified product in which the composition is completely blocked. [Claim 3] (In the formula, X is a bromine atom, i and j are each an integer of 1 to 4, and n is an average degree of polymerization of 0 to 40.) [Claim 3]
The flame-retardant resin composition according to claim 1, wherein the brominated polycarbonate flame retardant component (B) comprises a brominated bisphenol A type polycarbonate resin represented by the following general formula (II) and having a bromine content of 20% by weight or more. thing. [Formula 2] (wherein, X is a bromine atom, i and j are each integers of 1 to 4, l is an average degree of polymerization of 2 to 30, and Y and Z represent terminal groups. For example, [Chemical 3] [Claim 4] The flame retardant aid according to claim 1, wherein the flame retardant aid containing antimony pentoxide as a main component (C) is an antimony-based flame retardant aid represented by the general formula (III). Flame retardant resin composition. (Na2O)p ・Sb2O5 ・q
H2O(III) (p is 0.4~
0.9, and q is crystal water and represents a numerical value of 0 to 4. ) [Claim 5] The ethylene-ethyl acrylate copolymer of component (D) is 10-5 represented by the following general formula (IV).
A flame retardant resin composition according to claim 1 exhibiting an ethyl-acrylate content of 0%. [Formula 4] (wherein, A=0.5-0.9, B=0.1-0.5, A
+B=1, r indicates the average degree of polymerization. 6. The flame-retardant resin composition according to claim 1, wherein component (E) is hydrotalcite represented by general formula (V). Mg1-h Alh (OH)2 (CO
3) h/z ・kH2O (V) (However, h is 0.2 to 0.4, and k is crystal water and indicates a value of 2 or less.)