JPH06322265A - Flame-retardant thermoplastic resin composition - Google Patents

Abstract

PURPOSE:To provide a flame-retardant thermoplastic resin compsn. which is excellent in mechanical strengths and impact resistance. CONSTITUTION:The resin compsn. is prepd. by compounding 100 pts.wt. resin component comprising 50-95wt.% polyamide resin (a) and 5-50wt.% component consisting of polypropylene modified with an unsatd. carboxylic acid or its anhydride or consisting of the modified polypropylene and polypropylene (b), 5-100 pts.wt. glass fiber (c), a bromine flame retardant (d) in an amt. of 1-30 pts.wt. based on 100 pts.wt. the sum of components a, b, and c, and a flame retardant aid in an amt. of 1-10 pts.wt. based on 100 pts.wt. the sum of components a, b, and c in a wt. ratio of component d to component e of 1-5.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retarded thermoplastic resin composition, and more particularly to a flame-retarded thermoplastic resin composition having excellent mechanical strength and impact resistance.

[0002]

2. Description of the Related Art Polyamide resin has a gasoline barrier property,
Since it has excellent mechanical strength and heat resistance, it is suitable for plastic parts that replace various metals. For example, in order to reduce the weight of automobiles, polyamide resins have been used for radiator tanks and various other parts in engine rooms. In such a case, it is common to use nylon 6 or nylon 66, which is particularly excellent in strength and heat resistance, to which a reinforcing material such as glass fiber is added.

However, the polyamide resin has a problem that it is inferior in water resistance, moldability, chemical resistance and antifreeze resistance. The above-mentioned insufficient properties are generally possessed by polyolefins. Therefore, it is possible to mix a polyamide resin and polypropylene,
Since the polyamide resin and polypropylene have poor compatibility, it has been practiced to further mix modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof in such a composition system.

However, a composition system such as polyamide / modified polypropylene (added with polypropylene if necessary) / glass fiber is inferior in flame retardance, and therefore, it is used in applications where it is exposed to a high temperature for a long time, or when exposed to fire. There is the problem that it is not suitable for use in applications that may be in close proximity.

As a countermeasure against this, a flame retardant such as a halogen-antimony flame retardant and a flame retardant auxiliary such as Sb ₂ O ₃ have been added, but a composition obtained by adding the above flame retardant Since mechanical strength such as tensile strength and bending strength, impact resistance, etc. are significantly reduced, there is a problem that the use is limited.

Therefore, an object of the present invention is to provide a flame retarded thermoplastic resin composition which is excellent in mechanical strength and impact resistance.

[0007]

As a result of earnest research in view of the above objects, the present inventors have found that a composition comprising a polyamide resin, a polypropylene resin containing a modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof, and a glass fiber. In the product, it was found that if a specific flame retardant and a flame retardant aid are added in a range of a predetermined weight ratio, the composition can be flame retarded without lowering mechanical strength or impact resistance. The present invention was conceived.

That is, the flame-retardant thermoplastic resin composition of the present invention comprises (a) 50 to 95% by weight of polyamide resin, (b) polypropylene modified with an unsaturated carboxylic acid or an anhydride thereof,
Alternatively, 5 to 100 parts by weight of (c) glass fibers and 5 to 100 parts by weight of (a) + (b), and 5 to 100 parts by weight of polypropylene and the modified polypropylene, and (a) +
It contains 1 to 30 parts by weight of (d) a bromine-based flame retardant and (e) 1 to 10 parts by weight of a flame-retardant aid, based on 100 parts by weight of (b) + (c) in total. ) The weight ratio ((d) / (e)) of the brominated flame retardant to the flame retardant aid (e) is 1 to 5.

The present invention is described in detail below. [1] Composition component (a) Polyamide resin In the present invention, (a) the polyamide resin includes hexamethylenediamine, decamethylenediamine, dodecamethylenediamine, 2,2,4- or 2,4,4, -trimethylhexamethylene. Diamine, 1,3- or 1,4-bis (aminomethyl)
Aliphatic, alicyclic or aromatic diamines such as cyclohexane, bis (p-aminocyclohexylmethane), m- or p-xylylenediamine, and adipic acid, suberic acid, sebacic acid, cyclohexanedicarboxylic acid, terephthalic acid Polyamides prepared from aliphatic, cycloaliphatic or aromatic dicarboxylic acids such as isophthalic acid, 6
From polyamides made from aminocarboxylic acids such as aminocaproic acid, 11-aminoundecanoic acid, 12-aminododecanoic acid, polyamides made from lactams such as ε-caprolactam, ω-dodecalactam, and components thereof And a mixture of these polyamides. Specific examples include nylon 6, nylon 66, nylon 610, nylon 9, nylon 6/66, nylon 66/610, nylon 6/11, nylon 6/12, nylon 12, nylon 46, and amorphous nylon. . Of these, nylon 6 and nylon 66 are preferable in terms of good rigidity and heat resistance.

Although the molecular weight of the above polyamide resin is not particularly limited, those having a relative viscosity η _r (measured in JIS K6810, 98% sulfuric acid) of 0.5 or more are usually used, and those having a relative viscosity of 2.0 or more are excellent in mechanical strength. It is preferable in that

(B) Modified Polypropylene The modified polypropylene used in the present invention is a polypropylene modified with an unsaturated carboxylic acid or an anhydride thereof. As the unsaturated carboxylic acid or its anhydride, acrylic acid, monocarboxylic acid such as methacrylic acid, maleic acid, fumaric acid, dicarboxylic acid such as itaconic acid, maleic anhydride, dicarboxylic acid anhydride such as itaconic anhydride and the like. Among them, dicarboxylic acid and its anhydride are particularly preferable.

The polypropylene modified with an unsaturated carboxylic acid or its anhydride is not limited to a homopolymer of propylene, and contains 50% by mole or more of a propylene component.
It is also possible to use a random or block copolymer with another α-olefin, which is preferably contained in an amount of 80 mol% or more. Examples of the comonomer copolymerized with propylene include ethylene and other α-olefins, and ethylene is particularly preferable. Therefore, the term "polypropylene" as used herein should be understood to include not only propylene homopolymers but also copolymers. Melt flow rate of the above polypropylene (MFR, 230 ℃, 2.16kg
Load) is preferably 0.01 to 50 g / 10 min, especially 0.1 to 30
g / 10 minutes is preferred.

The content of unsaturated carboxylic acid or its anhydride in the modified polypropylene is preferably 0.01 to 5% by weight. If the amount of modification is less than 0.01% by weight, the effect of improving the compatibility between the polyamide resin and polypropylene by the addition of modified polypropylene is not sufficient, and if it exceeds 5% by weight, the mechanical strength decreases.

The modified polypropylene can be produced by either the melt-kneading method or the solution method. In the case of the melt kneading method, polypropylene, modifying unsaturated carboxylic acid (or acid anhydride) and a catalyst are charged into an extruder or a twin-screw kneader,
Knead while heating to a temperature of 180-250 ℃.
In the case of the solution method, the above-mentioned starting materials are dissolved in an organic solvent such as xylene and the stirring is performed. In any case, a usual radical polymerization catalyst can be used as a catalyst, for example, benzoyl peroxide, lauroyl peroxide, ditert-butyl peroxide, acetyl peroxide, tert-butyl peroxybenzoic acid, dicumyl peroxide, Peroxides such as peroxybenzoic acid, peroxyacetic acid and tertiary butyl peroxypivalate, and diazo compounds such as azobisisobutyronitrile are preferable. The amount of the catalyst added is about 1 to 100 parts by weight per 100 parts by weight of the unsaturated carboxylic acid for modification or its anhydride.

The modified polypropylene obtained as described above has a melt flow rate (MFR, 230 ° C., 2.16 kg load) of 0.1 to 500 g / 10 minutes, preferably 1 to 50 g / 10 minutes. If the melt flow rate is less than 0.1 g / 10 min, the moldability is not sufficient, while if it exceeds 500 g / 10 min, the mechanical strength decreases, which is not preferable.

In the present invention, it is also possible to use a mixture of the above-mentioned modified polypropylene and unmodified polypropylene. As the unmodified polypropylene, the same polypropylene as the above-mentioned polypropylene to be modified can be used.

In the case of a mixture of modified polypropylene and unmodified polypropylene, the mixing ratio of both is the sum of them.
As 100% by weight, the modified polypropylene is preferably 1% by weight or more, particularly preferably 5% by weight or more.

However, even in the case of a mixture of modified polypropylene and unmodified polypropylene, the content of unsaturated carboxylic acid or its anhydride in the modified polypropylene is 0.01 to 5% by weight based on 100% by weight of the entire mixture. Preferably.

In the case of the mixture, the melt flow rate (MFR, 230 ° C., 2.16 kg load) is 0.1 to 500 g / 10 min, especially 1 to 50, as in the case of the modified polypropylene alone.
It is preferably g / 10 minutes.

(C) Glass Fiber As the glass fiber, either chopped strand or roving can be used, but the average fiber diameter is 6 to 20 μm.
It is preferable that the aspect ratio is 100 to 500. In addition, it is preferable to use those which have been surface-treated with a silane coupling agent and / or a binding agent made of a polymer having a carboxyl group or an acid anhydride group. Such surface treatment improves the adhesion between the glass fiber and the polyamide resin.

(D) Brominated Flame Retardant In the present invention, a brominated flame retardant is used as the flame retardant. Examples of the brominated flame retardant include brominated polystyrene, brominated epoxy resin, polybromophenylene oxide, polypentabromobenzyl acrylate, ethylenebistetrabromophthalimide, and the like.
Of these, brominated polystyrene is preferred.

(E) Flame retardant aid Examples of the flame retardant aid include antimony trioxide, antimony pentoxide, sodium antimonate, aluminum hydroxide,
Examples thereof include magnesium hydroxide and zinc borate. Among these, antimony trioxide, antimony pentoxide and the like are preferable.

[2] Blending Ratio The blending ratio of each component as described above is the sum of the resin components ((a) polyamide resin + (b) modified polypropylene (adding polypropylene as necessary)) first. Is 100 to 100% by weight, the polyamide resin is 50 to 95% by weight, and the modified polypropylene (polypropylene is added if necessary) is 5 to 50% by weight. Polyamide resin is 50
If it is less than 5% by weight (modified polypropylene is more than 50% by weight), heat resistance and mechanical strength are insufficient, and if the polyamide resin exceeds 95% by weight (modified polypropylene is less than 5% by weight), molding Property and water resistance become insufficient, and the cost becomes high. Polyamide resin is especially 60-85
It is preferable that the modified polypropylene (polypropylene is added if necessary) is 15 to 40% by weight in weight%.

(C) The blending amount of glass fiber is the resin component ((a)
It is 5 to 100 parts by weight, preferably 10 to 80 parts by weight, based on 100 parts by weight of + (b)) in total. Glass fiber content is 5
If the amount is less than 100 parts by weight, the effect of improving the heat resistance and mechanical strength due to the composition is not sufficient, while if it exceeds 100 parts by weight, the moldability is deteriorated.

The amount of the (d) bromine-based flame retardant added is 1 to 100 parts by weight of the total of (a) + (b) + (c).
It is 30 parts by weight, preferably 2 to 25 parts by weight. When the amount of the brominated flame retardant added is less than 1 part by weight, sufficient flame retardant effect cannot be obtained, while when it exceeds 30 parts by weight, the mechanical strength decreases.

Furthermore, the amount of (e) flame retardant aid added is (a) +
1 to 10 parts by weight to 100 parts by weight of (b) + (c) in total,
It is preferably 2 to 8 parts by weight. Addition amount of flame retardant aid is 1
If it is less than part by weight, sufficient flame retardant effect cannot be obtained.
If it exceeds 10 parts by weight, not only the specific gravity becomes large, but also the mechanical properties are largely deteriorated.

However, in the present invention, the weight ratio ((d) / (e)) of the (d) brominated flame retardant to the (e) flame retardant auxiliary must be 1 to 5. If the weight ratio is less than 1 or more than 5, sufficient flame retarding effect cannot be obtained. preferable
Weight ratio of (d) brominated flame retardant to (e) flame retardant aid ((d) /
(e)) is 2-5.

[3] Other Components The flame-retardant thermoplastic resin composition of the present invention has other additives such as other inorganic fillers, heat stabilizers, and oxidants for the purpose of modification. An inhibitor, a light stabilizer, a plasticizer, an antistatic agent, a release agent, a foaming agent and the like can be added.

[4] Production Method The flame-retardant thermoplastic resin composition of the present invention comprising the above-mentioned components is prepared by mixing each of the above-mentioned components in a kneading device such as an extruder such as a single-screw extruder or a twin-screw extruder. It can be obtained by kneading in a molten state at 200 to 260 ° C.
The glass fiber, brominated flame retardant and flame retardant aid may be added from the beginning together with the polyamide resin and modified polypropylene (add polypropylene if necessary), or the resin components may be melt-kneaded to some extent. After doing, you may add in the middle.

[0030]

The flame-retardant thermoplastic resin composition of the present invention comprises a polyamide resin and a polypropylene resin containing a modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof.
Brominated flame retardant and flame retardant auxiliary are added to glass fiber in a predetermined blending ratio, so good flame retardancy can be achieved without lowering mechanical strength and impact resistance. Demonstrate.

Although the reason why such an effect is obtained is not necessarily clear, by blending the brominated flame retardant and the flame retardant auxiliary agent at a predetermined blending ratio, they are synergistically effective to form a polyamide resin. It is possible to make a composition flame-retardant without lowering the mechanical strength and impact resistance of a system comprising a polypropylene-based resin containing modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof and glass fibers. It is considered to be.

[0032]

The present invention will be described in more detail by the following examples. The following resin components and compounding agents were used as raw materials. [1] Polyamide resin Ny66: [M300, T300, Korshak-Za
0.051 m of terminal amino group measured by the method of myationa (reverse titration method) (Chem.Abs.40,4665, '46, ibid. 42,6152, '48)
Equivalent / g] [2] Polypropylene-Polypropylene (PP): [Melt flow rate (23
15g / 10min at 0 ℃, 2.16kg load) [3] Modified polypropylene with unsaturated carboxylic acid or its anhydride-Maleic anhydride modified polypropylene CMPP [addition amount of maleic anhydride 0.14% by weight, melt flow rate (230 ℃ , 2.16 kg load) 3 g / 10 minutes] [4] Glass fiber GF: [03M AFT2A, manufactured by Asahi Fiber Glass Co., Ltd., average fiber diameter 13 μm, aspect ratio 230, surface treated with maleic anhydride] [5] Flame retardant bromine Polystyrene BPs [Ferro, Pyrochech 68PB, weight average molecular weight 1000 to 12000, bromine content 67% by weight, specific gravity 2.10] [6] Flame retardant aid Sb ₂ O ₃ [Nippon Seiko Co., Ltd., ATOX-S] , Average particle size 0.5
μm]

The present invention will be described in more detail by the following examples. Examples 1 to 3 and Comparative Examples 1 to 2 Polyamide resin (Ny66), polypropylene (PP) and modified polypropylene (CMPP) with an unsaturated carboxylic acid or an anhydride thereof in proportions shown in Table 1, and flame retardants (BPs). And flame retardant aid (Sb ₂ O ₃ ) were dry blended, and the glass fiber (GF) was added in the mixing ratio shown in Table 1.
And kneading at 250 ° C with a 44 mmφ twin-screw extruder,
A pellet of the composition was obtained.

Test pieces were prepared from the obtained pellets by injection molding, and tensile strength, flexural strength, flexural strength when absorbing water, flexural modulus, Izod impact strength, flammability and specific gravity were measured. The results are also shown in Table 1.

Table 1 Composition (parts by weight ) Example 1 Example 2 Example 3 Comparative Example 1 Comparative Example 2 Comparative Example 3 Ny66 35 30 30 42 38 37 PP 18 15 15 21 19 18 CMPP 5 5 5 5 7 5 5 GF 30 30 30 30 30 30 BPs 9 16 15 − − 9 Sb ₂ O ₃ 3 4 5 − 8 1 Physical properties Tensile strength ⁽¹⁾ 1300 1350 1300 1700 1000 1300 Bending strength ⁽²⁾ 1900 1900 1850 2100 1300 1800 50% RH Water absorption ⁽³⁾ 1460 1520 1500 1600 950 1400 Izod Impact strength ⁽⁴⁾ 9.0 8.5 8.5 13 7.0 8.0 Flammability ⁽⁵⁾ V ₂ V ₀ V ₁ HB HB HB Specific gravity ⁽⁶⁾ 1.37 1.45 1.46 1.26 1.38 1.37

(1) Tensile strength: Measured according to ASTM D638 (unit: kg / cm ² ). (2) Bending strength: Measured by ASTM D790 (unit: kg / c
m ² ). (3) At 50% RH water absorption: For a test piece absorbed by immersing water in an amount equivalent to the equilibrium water absorption under conditions of 23 ° C. and 50% RH, to the above ( The bending strength of 2) was measured (the unit is kg / cm ² ). (4) Izod impact strength: Measured by ASTM D256 (unit: kg · cm / cm 2). (5) Flammability: Based on UL (Underwriters Laboratories: a typical American standard for safety inspections), length 5
A UL-SB94 combustion test was conducted using inch, width 1/2 inch, and thickness 1/16 inch test pieces, and each test piece falls under any of HB, V ₀ , V ₁ and V ₂ categories. I evaluated what to do. The above categories are V in order of good flame retardancy.
_It is classified into ₀ , V ₁ , V ₂ , and HB, and it has practically sufficient flame retardancy except for HB. (6) Specific gravity: Measured according to JIS K7112.

As is apparent from Table 1, Examples 1 to 3
The flame-retardant thermoplastic resin composition of, tensile strength, bending strength,
The flexural strength, flexural modulus, and Izod impact strength at the time of absorbing water were all at good levels, and the flame retardancy was sufficient for practical use.

[0038]

As described in detail above, the flame-retardant thermoplastic resin composition of the present invention comprises a polyamide resin, a polypropylene resin containing a modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof, and a glass. A brominated flame retardant and a flame retardant auxiliary are added to the fiber so as to have a predetermined blending ratio, so good flame retardancy is exhibited without lowering mechanical strength and impact resistance. To do.

The composition of the present invention as described above is particularly suitable for use in automobile engine parts such as fan shrouds, parts for air conditioners, electric equipment and the like.

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Claims (1)

[Claims] 1. (a) 50 to 95% by weight of polyamide resin,
(b) Modified polypropylene with an unsaturated carboxylic acid or an anhydride thereof, or 5 to 50% by weight of polypropylene and the modified polypropylene, and (a) + (b) in total of 10
0 to 5 parts by weight of (c) 5 to 100 parts by weight of glass fiber,
Based on 100 parts by weight of the above (a) + (b) + (c), (d)
A bromine-based flame retardant 1 to 30 parts by weight and (e) 1 to 10 parts by weight of a flame retardant aid, and the weight ratio of the (d) brominated flame retardant and (e) flame retardant aid (( d) / (e)) is 1-5, The flame-retardant thermoplastic resin composition characterized by the above-mentioned.