JPH07133411A - Flame retardant polybutylene terephathalate-based resin composition - Google Patents

Abstract

PURPOSE:To obtain a composition excellent in mechanical properties, heat resistance and hue and capable of providing moldings in good moldability and a short time and high productivity by blending a PBT-based resin with a brominated polycarbonate and antimony trioxide. CONSTITUTION:This composition is obtained by blending (A) 100 pts.wt. of a polybutylene terephthalate-based resin with (B) 5-40 pts.wt. of a brominated polycarbonate and (C) 2-20 pts.wt. of antimony trioxide having <=1.5mum average particle diameter. The component B is preferably a tetrabromobisphenol A type polycarbonate having 1000-100000 weight-average molecular weight.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant polybutylene terephthalate resin composition. More particularly, it relates to a flame-retardant polybutylene terephthalate-based resin composition having excellent mechanical properties, heat resistance, hue, and excellent moldability.

[0002]

2. Description of the Related Art Polybutylene terephthalate resins are excellent in heat resistance, solvent resistance, electrical properties, moldability and the like, and can be easily made flame-retardant by adding a flame retardant. It is widely used for various applications such as electric / electronic parts, automobile parts, and mechanical parts. In particular, among the flame retardants, molded articles obtained from the polybutylene terephthalate-based resin composition containing the brominated polycarbonate flame retardant are polybutylene terephthalate-based compounds containing other flame retardants such as brominated polystyrene and brominated acrylic resin. Compared with molded products obtained from resin compositions, various properties such as hue, heat resistance and mechanical properties are excellent, and brominated polycarbonate is widely used as a flame retardant for polybutylene terephthalate resins from this point. ing.

However, since brominated polycarbonate has a carbonate bond, which is one kind of ester bond, in its molecule, it undergoes an transesterification reaction with polybutylene terephthalate during melting to lower the crystallinity of polybutylene terephthalate. As a result, the solidification rate of polybutylene terephthalate becomes slower, for example, when injection molding is performed, it does not solidify rapidly in the mold and requires a long demolding time, which lengthens the molding cycle and increases productivity. Has the disadvantage that it decreases.

[0004]

The object of the present invention is to improve the properties such as the above-mentioned excellent hue, heat resistance and mechanical properties obtained by blending a polybutylene terephthalate resin with a brominated polycarbonate. It is to provide a flame-retardant polybutylene terephthalate-based resin composition which is excellent in moldability while being kept and can be molded in a short time.

[0005]

Means for Solving the Problems As a result of intensive studies conducted by the present inventor to achieve the above object, as a result, a flame retardant composed of brominated polycarbonate was treated with antimony trioxide having a specific particle size. When used as an auxiliary agent, the crystallization rate of polybutylene terephthalate does not slow down even in the presence of brominated polycarbonate, and it solidifies quickly in the mold when molding, making the target molded product efficient in a short molding time. The present invention has been completed by finding that they can be manufactured well.

That is, the present invention is a flame-retardant polybutylene terephthalate resin composition containing a polybutylene terephthalate resin, a brominated polycarbonate, and antimony trioxide having an average particle size of 1.5 μm or less. .

In the polybutylene terephthalate resin (hereinafter referred to as "PBT resin") used in the present invention, at least 90 mol% of the acid component constituting the PBT resin is terephthalic acid or its ester-forming derivative, and diol. At least 90 mol% of the component is a polyester resin composed of 1,4-butanediol, and 10 mol%
Other copolymerized acid components and / or other copolymerized diol components may be used within the following ranges. At that time, when an ester-forming derivative of terephthalic acid is used as an acid component, a dialkyl ester, a diaryl ester of terephthalic acid or the like can be used.

Examples of other copolymerizable acid components that can be used in the range of 10 mol% or less include aromatic dicarboxylic acids such as phthalic acid, isophthalic acid, naphthalene-1,4-dicarboxylic acid and diphenyldicarboxylic acid; Aliphatic dicarboxylic acids such as adipic acid, sebacic acid, mazelaic acid, succinic acid and oxalic acid; oxycarboxylic acids such as p-hydroxybenzoic acid and p-hydroxymethylbenzoic acid; or ester-forming derivatives thereof. These copolymeric acid components may be used alone or in combination of two or more.

Examples of the copolymerized diol component which can be used in the range of 10 mol% or less include ethylene glycol, propylene glycol, neopentyl glycol, 1,5-pentanediol, 3-methyl-1,5.
-Pentanediol, 1,6-hexanediol, 1,
Aliphatic diols having 2 to 10 carbon atoms such as 9-nonanediol, 2-methyl-1,8-octanediol and decamethylenediol; alicyclic diols such as cyclohexanediol; 2,2-bis (4-hydroxyphenyl) ) Aromatic diols such as propane (bisphenol A); polyalkylene glycols such as polyethylene glycol, polytrimethylene glycol, and polytetramethylene glycol, and the like. These copolymerized diol components may be used alone. Alternatively, two or more kinds may be used.

The method for producing the PBT-based resin is not particularly limited, and it is conventional to use the above-mentioned acid component mainly consisting of terephthalic acid or its ester-forming derivative and the above-mentioned diol component mainly consisting of 1,4-butanediol. Any of the known aromatic polyesters produced by the transesterification reaction or the direct esterification reaction can be used.

In the present invention, the intrinsic viscosity of the PBT resin measured at 30 ° C. using a phenol / tetrachloroethane (1: 1 weight ratio) mixed solvent is 0.5-1.
It is preferable to use one in the range of 3 dl / g,
A PBT resin in the range of 0.7 to 1.1 dl / g is more preferable. When the intrinsic viscosity of the PBT resin is less than 0.5 dl / g, the mechanical performance of a molded article obtained from the PBT resin composition may be deteriorated, while the intrinsic viscosity of the PBT resin is 1.3 dl. If a PBT resin that exceeds / g is used, the melt viscosity at the time of molding becomes too high and the moldability decreases, and molding tends to be difficult, especially in the case of injection molding.

In the PBT resin composition of the present invention, brominated polycarbonate is blended with the above PBT resin as a flame retardant. A preferred example of the brominated polycarbonate used in the present invention is a brominated bisphenol type polycarbonate, and examples of the brominated bisphenol type polycarbonate at that time include brominated bisphenol A, bisphenol F, bisphenol S, etc. The brominated bisphenol type polycarbonates based on various brominated bisphenols can be used, and among them, the brominated bisphenol A type polycarbonates are particularly preferable. As a more specific example, tetrabromo-bisphenol A
(For example, 3,3 ', 5,5'-tetrabromobisphenol A), dibromo-bisphenol A, hexabromobisphenol A, and other brominated polycarbonates obtained by reacting phosgene with the brominated bisphenol A, or the above. Examples thereof include brominated polycarbonate obtained by reacting phosgene with a mixture of one or more brominated bisphenol A and bisphenol A that has not been brominated.

Further, in the present invention, as the brominated polycarbonate, tetrahydrofuran is used as a solvent, and GPC is used.
The weight average molecular weight when measured by
Those of 0000 are preferably used.

The blending amount of brominated polycarbonate is PB
The amount is preferably 5 to 40 parts by weight, and particularly preferably 15 to 30 parts by weight, based on 100 parts by weight of the T-based resin. If the blending amount of the brominated polycarbonate is less than 5 parts by weight, it becomes difficult to obtain a sufficient flame retarding effect, while if it exceeds 40 parts by weight, the mechanical performance of the obtained molded article deteriorates and the amount of harmful volatile components is increased. Is likely to occur.

In the PBT resin composition of the present invention, it is important to use a brominated polycarbonate as a flame retardant. Even though it is a brominated polymer, for example, a brominated acrylic resin, brominated polystyrene or brominated phenoxy resin. When such a compound is used, the heat resistance and hue of the molded product obtained from the PBT resin composition are inferior, and mechanical properties such as tensile strength are also inferior depending on the type of flame retardant.

In the present invention, antimony trioxide having an average particle size of 1.5 μm or less is used as a flame retardant auxiliary together with the brominated polycarbonate flame retardant. This antimony trioxide functions as a flame retardant auxiliary agent as well as a crystal nucleating agent. When the average particle size of antimony trioxide exceeds 1.5 μm, it does not function as a nucleating agent, the solidification of the PBT resin composition is delayed during molding, and moldability becomes poor. The average particle size of antimony trioxide is more preferably 1.0 μm or less, and particularly preferably 0.01 to 0.5 μm. The average particle size of antimony trioxide used in the present invention is a value measured as follows.

Method for measuring the average particle size of antimony trioxide : Using water as a dispersion medium and lignin sulfonate as a dispersant, the average particle size of antimony trioxide is determined by a centrifugal sedimentation method. The average particle size is represented by the diameter when the average weight reaches 50% by weight.

Antimony trioxide may be subjected to various surface treatments and other treatments, if necessary, as long as it does not hinder its functions as a flame retardant aid and a crystal nucleating agent. The compounding amount of antimony trioxide is 100% PBT resin.
The amount is preferably 2 to 20 parts by weight, more preferably 5 to 15 parts by weight, based on parts by weight. If the compounding amount of antimony trioxide is less than 2 parts by weight, it becomes difficult to obtain a sufficient flame retarding effect, while if it exceeds 20 parts by weight, the toughness tends to be lowered. If necessary, other known nucleating agents such as talc and other flame retardant aids such as boron oxide, zirconium oxide and iron oxide may be used together with antimony trioxide.

Further, the PBT resin composition of the present invention may contain glass fiber if necessary, and when glass fiber is blended, a molded article having more excellent mechanical properties can be obtained. When glass fiber is compounded, the compounding amount is usually added in an amount within the range of not more than 80% by weight based on the total amount.

Further, the PBT resin composition of the present invention contains, in addition to the above-mentioned components, various conventionally known additives such as a releasing agent, a stabilizer, an antistatic agent, a dye / pigment and a plasticizer, if necessary. , An inorganic filler, etc. may be contained. Further, the PBT resin composition of the present invention may contain other organic polymers such as polyethylene terephthalate, polypropylene and ethylene-vinyl acetate copolymer.

The method for preparing the flame-retardant PBT resin composition of the present invention is not particularly limited, and any known method used for preparing the resin composition can be adopted. For example, sufficiently dried chips can be used. Brominated polycarbonate, antimony trioxide, and if necessary, glass fiber, other additives, organic polymers, etc., are added to the PBT-based resin and mixed in advance with a mixer such as a tumbler or a Henschel mixer. After that, it can be fed to a single-screw or twin-screw extruder, melt-kneaded, extruded, and cut to prepare pellets and other resin compositions in other shapes.

The flame-retardant PBT resin composition of the present invention can be molded by using a molding method and a molding apparatus generally used for polyester resins. For example,
It can be molded by any molding method such as injection molding, extrusion molding, press molding, blow molding, calender molding, etc., so that it can be used for electrical parts, electronic parts, mechanical parts, automobile parts, pipes, sheets, films, daily necessities etc. It is possible to manufacture a molded product of any shape and application, and it is particularly suitable for manufacturing various molded products by injection molding or the like.

[0023]

[Examples] The present invention will be specifically described below with reference to Examples and Comparative Examples, but the present invention is not limited thereto.
Each value in the following examples and comparative examples was determined as follows.

Average particle size of antimony trioxide : As described above, it was determined by the centrifugal sedimentation method using water as a dispersion medium and lignin sulfonate as a dispersant.

Crystallization temperature (Tcc) : A 10 mg sample was cut out from the PBT resin pellet of each Example or Comparative Example, and the crystallization temperature was measured by DSC. The measurement is performed by raising the temperature from room temperature to 290 ° C. at a heating rate of 20 ° C./min.
After holding at 0 ° C for 10 minutes, the temperature was lowered at a rate of 20 ° C / minute.

Gate sealing time : Using the pellets of the PBT resin composition of each Example or Comparative Example as a molding material, and using an 80 ton injection molding machine, a cylinder temperature of 2
Under the conditions of 60 ° C. and mold temperature of 70 ° C., a side-gate type mold having a box-shaped cavity [cavity inner diameter = length 10 mm × width 10 mm × depth 20 mm: cavity gap (wall thickness) 1. 2mm: Gate size = 1mm x
3 mm] injection-molded and cooled and solidified after injection
The time until the gate was sealed with the T resin composition was measured and used as the gate sealing time.

Solidification time : PBT of each Example or Comparative Example
Using a pellet of a resin composition as a molding material,
Mold for connector production under the conditions of cylinder temperature of 260 ℃ and mold temperature of 70 ℃ using a ton injection molding machine
(28 pins: mold cavity volume 15 cm ³ ) was injection-molded, and after injection, the shortest time until the molded product in the mold could be taken out without deformation was measured and set as the solidification time.

Tensile Strength : PBT of each Example or Comparative Example
Using a pellet of a resin composition as a molding material,
Ton injection molding machine was used to produce JIS No. 1 test pieces under the conditions of a cylinder temperature of 260 ° C. and a mold temperature of 70 ° C., and the tensile strength of the JIS No. 1 test pieces was measured according to the method of JIS K7113. It was measured.

Dry heat deterioration test : A JIS No. 1 test piece prepared in the same manner as above was put in a heating oven to obtain 150
The tensile strength when heated at 0 ° C. for 20 days was measured in the same manner as above, and the strength retention ratio to the initial tensile strength before heating was obtained.

Thermal discoloration test : J prepared in the same manner as above
The hue of the IS 1 test piece was measured using a color computer, the test piece was heated in an oven at 150 ° C. for 20 days, and the hue at that time was measured in the same manner.
Based on IS Z8729, the change amount ΔE from the initial value (value before heating) was obtained.

Flame retardance test : PB of each Example or Comparative Example
Using pellets of the T-based resin composition as a molding material, 1
Cylinder temperature 260 using 00 ton injection molding machine
Test piece for flame retardancy evaluation under conditions of ℃ and mold temperature of 70 ℃ (length 127 mm × width 12.7 mm × thickness 0.8 mm)
Was prepared, and flame retardancy was evaluated according to the method of UL-94 (vertical combustion test).

Example 1 Intrinsic viscosity is 0.85 dl /
g of PBT resin [“KL263F” manufactured by Kuraray Co., Ltd.) 1
In 100 parts by weight (hereinafter abbreviated as "part"), as shown in Table 1 below, brominated polycarbonate flame retardant ("BC-58" manufactured by Great Lakes: number average molecular weight 3500; bromine content 53% by weight) 30 Part and 13 parts of antimony trioxide (average particle size 0.3 μm) were mixed with a twin-screw extruder (manufactured by Nippon Steel Co., Ltd.,
φ44 mm), melt-kneaded at 250 ° C., extruded from the die, cooled and cut to a diameter of 2 mm, length of 3 mm
Pellets were produced. The crystallization temperature (Tcc) was measured using this pellet. Further, a box-shaped molded product, a connector and a test piece were prepared as described above, and the gate sealing time, the setting time and the tensile strength were measured, and the dry heat resistance test, the thermal discoloration test and the flame retardancy test were performed. The results are shown in Table 1 below.

Example 2 The procedure of Example 1 was repeated except that antimony trioxide having an average particle size of 1.0 μm was used. The results are shown in Table 1 below.

Examples 3 to 4 The same procedure as in Example 1 was carried out with the blending amounts of brominated polycarbonate and antimony trioxide (average particle size 0.3 μm) shown in Table 1. The results are shown in Table 1 below.

Example 5 Example 5 was repeated except that 50 parts of glass fiber (“ECS-03T-187” manufactured by Nippon Electric Glass Co., Ltd.) was further added. The results are shown in Table 1.

Comparative Example 1 The procedure of Example 1 was repeated except that 13 parts of antimony trioxide having an average particle size of 7.0 μm were mixed. The results are shown in Table 1.

Comparative Example 2 The same procedure as in Comparative Example 1 was carried out by adding 10 parts of talc (“Micro White # 5000S” manufactured by Hayashi Kasei). The results are shown in Table 1.

Comparative Example 3 The procedure of Example 1 was repeated except that a brominated acrylic resin flame retardant (“PBB-PA” manufactured by Dead Sea Bromine) was used instead of the brominated polycarbonate. The results are shown in Table 1.

Comparative Example 4 Brominated phenoxy resin flame retardant instead of brominated polycarbonate (“Y” manufactured by Tohto Kasei)
PB-43C ") was used, and the same procedure as in Example 1 was performed. The results are shown in Table 1.

Comparative Example 5 Brominated polystyrene flame retardant (“Pyrocheck 68PB” manufactured by Nissan Ferro) instead of brominated polycarbonate (“YPB-43 manufactured by Toto Kasei”)
The same procedure as in Example 1 was carried out except that "C") was used. The results are shown in Table 1.

[0041]

[Table 1]

From the results in Table 1 above, in the case of Examples 1 to 5, the solidification rate was high (solidification time was short), the moldability was good in a short molding time, the mechanical strength and the heat resistance (dry heat deterioration resistance and Molded articles excellent in all of (heat discoloration resistance) and flame retardancy can be obtained, whereas in Comparative Examples 1 and 2, the solidification rate is slow (solidification time is long), and the moldability is poor. In Comparative Example 3, Comparative Example 4, and Comparative Example 5, in which a brominated acrylic resin flame retardant, a brominated phenoxy resin flame retardant, or a brominated polystyrene flame retardant is used, the resulting molded articles have low mechanical strength and dry heat resistance. It can be seen that there are drawbacks such as inferior properties and large thermal discoloration.

[0043]

When the flame-retardant PBT resin composition of the present invention is used, a molded article excellent in various properties such as mechanical properties, heat resistance, hue and flame retardancy can be cooled and solidified for a short time. In time, it can be efficiently produced with good moldability, and productivity can be improved.

Claims (2)

[Claims] 1. A flame-retardant polybutylene terephthalate-based resin composition comprising a polybutylene terephthalate-based resin, a brominated polycarbonate, and antimony trioxide having an average particle size of 1.5 μm or less. 2. A polybutylene terephthalate resin 10
0 to 40 parts by weight of brominated polycarbonate
The flame-retardant polybutylene terephthalate resin composition according to claim 1, which contains 2 parts by weight and 2 parts by weight of antimony trioxide.