JP2000273269A - Flame-retardant styrene-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the subject composition, composed of a rubber-modified styrene-based resin and organophosphorus compound containing a cyclic phosphate ester compound, excellent in resistance to heat, good in resistance to impact, and having flame-retardant function of melting to drip down when ignited. SOLUTION: This composition is composed of (A) 100 pts.wt. of a rubber- modified styrene-based resin having a reduced viscosity of 0.61 to 1.50 dl/g and (B) 1 to 70 pts.wt. of an organophosphorus compound containing a cyclic phosphate ester compound, shown by formula I [R1 and R2 are each a monovalent aromatic shown by formula II (Ar is phenyl, naphthyl or the like; (n) is 0 to 5; and R3 is a 5-14C aryl)] at 30 wt.% or more. It is preferable that the component A contains a rubber-like polymer component at 1 to 10 wt.%. It is also preferable that rate of decrease in deflection temperature under load, defined by [(x-y)/x]×100 (%), is 20% or less, wherein (x) is deflection temperature under load ( deg.C) of the component A and (y) is deflection temperature under load ( deg.C) of the composition composed of the components A and B.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a styrene resin composition having excellent heat resistance, good impact resistance and high flame retardancy.

[0002]

2. Description of the Related Art Styrene resins are used in various fields such as office automation equipment parts, home appliance parts, and automobile parts because of their excellent impact resistance and excellent moldability. Its use is limited because of its flammability. As a method of making a styrene-based resin flame-retardant, it is known to add a halogen-based, phosphorus-based, or inorganic-based flame retardant, thereby achieving some degree of flame retardancy. However, in order to enhance product safety, regulations on flame-retardant tests for office automation equipment and molded products of home electric appliances have been stricter year after year based on the subject 94 of the United States underwriters laboratory (UL). Therefore, higher flame retardancy is required.

Heretofore, as a method for improving the flame retardancy of a styrene resin, for example, a resin composition comprising a styrene resin, a nitrogen compound such as melamine, a polyol and an organic phosphate (JP-A-4-117442), A self-extinguishing self-extinguishing styrene resin composition comprising a rubber-modified styrene resin having a specific average rubber particle diameter and a halogen-based flame retardant (JP-B-6-43542) is known. However, the resin compositions disclosed in these publications have a problem that flame retardancy is not sufficient and the range of use is limited.

Further, in recent years, it has been reported that an organic compound containing halogen has an adverse effect on the environment, and non-halogenation has been actively promoted mainly in Europe. Demand for non-halogen flame retardants has also increased,
The development of non-halogen flame retardants for each resin has been actively carried out. However, it has been considered difficult to make halogen-free flame retardants of styrene resins because of their flammability.

As a known technique in this field, Japanese Patent Application Laid-Open No.
JP-A-176396 and JP-A-8-120152 disclose a resin composition of a specific rubber-modified styrenic resin and a phosphorus-based flame retardant. Specifically, triphenyl phosphate and its derivatives as a phosphorus-based flame retardant are disclosed. It has been shown that red phosphorus is used, and the flame-retardant self-extinguishing property of the molten dripping is exhibited. However, triphenyl phosphate and its derivatives increase the fluidity by its plasticity effect, facilitate ignition melting dropping, and exhibit flame retardancy. There is a drawback of poor sex. When red phosphorus is used, toxic phosphine gas is easily generated during extrusion molding of the resin composition, and there are problems such as difficulty in handling red phosphorus, and the obtained resin composition has a brown color peculiar to red phosphorus. However, there is a disadvantage that the range of use is limited.

JP-A-8-31278 discloses a rubber-modified styrenic resin, an organic phosphorus compound monomer and an organic phosphorus compound condensate, and silicone oil. A self-extinguishing melt-extinguishing styrene-based flame-retardant resin composition characterized by containing -100% by weight is disclosed. Specifically, a rubber-modified polystyrene having a reduced viscosity of 0.53 dl / g is used, and such a resin composition also has a disadvantage that heat resistance and impact resistance are poor and practicality is poor.

As described above, the conventional rubber-modified styrene-based flame-retardant resin composition achieves flame retardancy, but is inferior in heat resistance, particularly for applications requiring high heat resistance such as OA equipment housings. It is difficult to use and its improvement is required.

[0008]

SUMMARY OF THE INVENTION An object of the present invention is to provide a rubber-modified styrenic resin composition which has excellent heat resistance and good impact resistance and also has a flame-retardant performance of an ignition melting dropping type. .

The present inventor has conducted intensive studies to achieve the above object, and as a result, a rubber-modified styrenic resin having a specific reduced viscosity has a specific amount of an organic phosphorus compound containing a specific cyclic phosphate compound. It has been found that by blending, a resin composition having particularly excellent heat resistance, good impact resistance and good flame retardancy can be obtained, and the present invention has been achieved.

[0010]

That is, according to the present invention, there are provided (A) a rubber-modified styrene resin (component (A)) having a reduced viscosity of 0.61 to 1.50 dl / g; It consists of an organic phosphorus compound (B component) containing at least 30% by weight of the cyclic phosphate compound represented by (1).
A flame-retardant styrenic resin composition characterized by being 0 parts by weight is provided.

[0011]

Embedded image

(In the formula, R ¹ and R ² may be the same or different and are a monovalent aromatic group represented by the following general formula (2).)

[0013]

Embedded image

(Wherein Ar is a phenyl group, a naphthyl group,
Select from anthryl, pyridyl and triazyl groups
N represents an integer of 0 to 5
You. R ^ThreeMay be the same or different
And a portion bonded to phosphorus via an oxygen atom on Ar
May be attached to any part other than
, Propyl, butyl or its bonding group to Ar
Oxygen, sulfur or an aliphatic hydrocarbon group having 1 to 4 carbon atoms
And represents an aryl group having 5 to 14 carbon atoms. )

The rubber-modified styrenic resin used as the component A in the present invention is a polymer obtained by dispersing a rubbery polymer in the form of particles in a matrix mainly composed of an aromatic vinyl polymer. It can be obtained by adding a monomer mixture containing an aromatic vinyl monomer as an essential component in the presence of coalescence and subjecting it to a known bulk polymerization, bulk suspension polymerization, solution polymerization or emulsion polymerization.

Examples of the rubbery polymer include diene rubbers such as polybutadiene, poly (styrene-butadiene), poly (acrylonitrile-butadiene), saturated rubber obtained by hydrogenating the diene rubber, isoprene rubber,
Examples include chloroprene rubber, acrylic rubber such as polybutyl acrylate, and ethylene-propylene-diene monomer terpolymer (EPDM). Diene rubber is particularly preferable.

The aromatic vinyl monomer which is an essential component in the graft copolymerizable monomer mixture to be polymerized in the presence of the rubbery polymer is, for example, styrene, α-methylstyrene, paramethylstyrene, etc. And styrene is most preferred.

The rubbery polymer component in the rubber-modified styrenic resin is preferably 1 to 10% by weight, more preferably 2 to 8.5% by weight, and the aromatic vinyl polymer component is preferably 99-90% by weight, more preferably 98
９91.5% by weight. Within this range, the balance of heat resistance, impact resistance and rigidity of the obtained resin composition is improved, and the unsaturated bond is less likely to be oxidized and the thermal stability is excellent.

The reduced viscosity η _{sp /} C (0.5 g / dl) which is a measure of the molecular weight of the rubber-modified styrenic resin in the present invention.
Is measured at 30 ° C.) from 0.61 to 1.5
0 dl / g, preferably 0.61 to 1.20 dl
/ G, more preferably 0.61 to 1.00 dl /
g. Reduced viscosity η _sp / C of rubber-modified styrenic resin
Means for satisfying the above-mentioned conditions include adjustment of the polymerization initiator, the polymerization temperature, and the amount of the chain transfer agent. When the reduced viscosity is low, heat resistance and impact resistance are poor.

In the present invention, the organic phosphorus compound used as the component B is at least 30% by weight, preferably at least 50% by weight, more preferably at least 60% by weight of the cyclic phosphate compound represented by the above general formula (1).
An organic phosphorus compound containing at least 80% by weight, more preferably at least 80% by weight. Further, it is also preferable to use substantially only such a cyclic phosphate compound as the organic phosphorus compound. By using a specific amount or more of such a cyclic phosphate compound, a styrene resin composition having excellent flame retardancy and impact resistance can be obtained.

In the general formula (1), R ¹ and R ²
May be the same or different, and the above general formula (2)
And in the general formula (2), Ar is any one group selected from a phenyl group, a naphthyl group, an anthryl group, a pyridyl group and a triazyl group, preferably a phenyl group Wherein n is an integer of 0 to 5, preferably 0 to 4, and R ³ may be the same or different, and a moiety bonded to phosphorus via an oxygen atom on Ar. And methyl, ethyl, propyl (including isomers), butyl (including isomers), or a group bonded to Ar is oxygen, sulfur, or a group having 1 to 4 carbon atoms. 5-14 carbon atoms via an aliphatic hydrocarbon group, preferably 6-carbon atoms
14 aryl groups.

In the general formula (1), preferred examples of R ¹ and R ² include phenyl, cresyl, xylyl, trimethylphenyl, 4-phenoxyphenyl, cumyl, naphthyl, Examples thereof include a benzylphenyl group, and a phenyl group is particularly preferable.

Such a cyclic phosphate compound is basically obtained by reacting an adjacent diol skeleton with phosphorus oxytrichloride and then appropriately reacting a phenolic hydroxyl group. Such a reaction is described, for example, in Japanese Patent Application Laid-Open No. 9-1.
No. 83786, the technique disclosed in R.
M. McConnell et al. Org. Chem. ,
The method described in Vol. 24, pp. 630-635 (1959) is employed.

Specifically, such a cyclic phosphate compound used in the present invention is obtained by reacting pentaerythritol with phosphorus oxytrichloride and then reacting with phenol,
It is obtained by reacting 5-dimethylphenol, cresol and the like. Alternatively, after a part of chlorine of phosphorus oxytrichloride is modified with these phenols in advance,
It is also possible to react in the same manner.

In the above organic phosphorus compound of the component B, triphenyl phosphate, bis (nonylphenyl) phenyl phosphate, nonylphenyldiphenyl phosphate and triphenyl phosphate are used as components other than the cyclic phosphate compound represented by the general formula (1). At least one compound selected from the group consisting of tris (nonylphenyl) phosphate is preferably used.

The compounding amount of the organic phosphorus compound (component B) is 1 to 70 parts by weight, more preferably 2 to 5 parts by weight, based on 100 parts by weight of the rubber-modified styrene resin (component A).
It is 5 parts by weight, more preferably 3 to 35 parts by weight. 1
If the amount is less than 10 parts by weight, the obtained resin composition is inferior in flame retardancy, and if it is more than 70 parts by weight, it causes a decrease in the physical properties of the resin composition, particularly impact resistance, and is disadvantageous in terms of cost. Absent.

In general, it is known that the heat resistance (the deflection temperature under load) is greatly reduced by adding an organic phosphorus compound to a rubber-modified styrene resin. However, in the resin composition obtained by the present invention, the rate of decrease in the deflection temperature under load from the rubber-modified styrene resin used is preferably 20% or less, preferably 16% or less, more preferably 15% or less. In the range of such a reduction rate, it cannot be a serious disadvantage in practical use, and is characterized by maintaining the original high heat resistance of the rubber-modified styrene resin. Here, the rate of decrease in the deflection temperature under load is determined by calculating the deflection temperature under load x (° C.) of the rubber-modified styrene-based resin as the component A and A
In relation to the deflection temperature under load y (° C.) of the styrenic resin composition comprising the component B and the component B, ｛(xy) /
It is calculated by the formula of x｝ × 100 (%). In addition, the resin composition of the present invention was prepared by applying a load of 1.81 MPa (1) using a 1/4 inch test piece by a method based on ASTM-D648.
The value of the deflection temperature under load measured at 8.5 kgf / cm ² ) is preferably in the range of 60 to 80 ° C, more preferably in the range of 65 to 80 ° C.

The resin composition obtained according to the present invention preferably has a reduction rate of Izod impact strength from the rubber-modified styrene resin used of 5 to 35%, more preferably 5 to 30%, In the range of such a decrease rate, it cannot be a serious disadvantage in practical use, and is characterized by maintaining the original high impact resistance of the rubber-modified styrene resin. Here, the reduction rate of the Izod impact strength is the Izod impact strength v (J / m) of the rubber-modified styrene resin of the component A.
And the Izod impact strength w (J / m) of the styrenic resin composition comprising the A component and the B component,
It is calculated by the formula of {(v−w) / v} × 100 (%). In addition, the resin composition of the present invention comprises ASTM-D256
The value of the Izod impact strength measured at 25 ° C. and 60 Kg using a 1/8 inch test piece with a V notch by a method conforming to the standard is preferably 200 to 800 J / m, more preferably 250 to 700 J / m. .

The flame-retardant styrenic resin composition of the present invention may contain various flame-retardant aids such as silicone oil. Such silicone oils have a polydiorganosiloxane skeleton, preferably polydiphenylsiloxane, polymethylphenylsiloxane, polydimethylsiloxane, or any copolymer or mixture thereof, and among them, polydimethylsiloxane is preferably used. . Its viscosity is preferably 0.8-5
000 centipoise (25 ° C.), more preferably 10 to
1000 centipoise (25 ° C), more preferably 5
The viscosity is in the range of 0 to 500 centipoise (25 ° C.), and the viscosity is preferably excellent in flame retardancy. The amount of the silicone oil to be blended is 10%.
The range of 0.5 to 10 parts by weight relative to 0 parts by weight is preferable.

The flame-retardant styrenic resin composition of the present invention may contain various additives such as antioxidants, ultraviolet absorbers, deterioration inhibitors such as light stabilizers, lubricants, antistatic agents, release agents, etc. Molding agents, plasticizers, reinforcing fibers such as glass fiber and carbon fiber, fillers such as talc, mica, wollastonite,
A coloring agent such as a pigment may be added. The amount of the additive to be used can be appropriately selected according to the type of the additive within a range that does not impair heat resistance, impact resistance, mechanical strength, and the like.

The flame-retardant styrenic resin composition of the present invention comprises:
Usually, the A component, the B component, and if necessary, other components are premixed using a mixer such as a V-type blender, a super mixer, a super floater, and a Henschel mixer. Mixed. As a kneader, various melt mixers, for example,
A kneader, a single-screw or twin-screw extruder can be used, among which the styrene-based resin composition is melted at a temperature of about 150 to 250 ° C, preferably about 170 to 220 ° C using a twin-screw extruder or the like, A method in which a liquid component is injected by a side feeder, extruded, and pelletized by a pelletizer is preferably used.

The flame-retardant styrenic resin composition of the present invention comprises:
In particular, it has good heat resistance and is useful as a material for molding various molded articles such as office automation equipment parts, home electric appliance parts, and automobile parts. Such a molded product can be prepared by a conventional method, for example, using a flame-retardant styrenic resin composition in the form of a pellet using an injection molding machine, for example, from 160 to 22%.
It can be manufactured by injection molding at a cylinder temperature of about 0 ° C.

[0033]

EXAMPLES The present invention will be described below with reference to examples.
The present invention is not limited to these examples. The evaluation was performed by the following method.

(1) Flame Retardancy (UL-94 Evaluation) Flame retardancy is measured by using a test piece having a thickness of 1/8 inch and is specified in UL-94 of the United States UL standard as an evaluation scale of flame retardancy. The evaluation was performed according to the vertical combustion test. In all the test pieces, the flame after removing the flame was burned within 30 seconds, and the fire was dropped and extinguished was V-2.

(2) Reduced viscosity (η _sp / C) Methyl ethyl ketone 18 was added to 1 g of the rubber-modified styrene resin.
and a mixed solvent of methanol and 2 ml of methanol.
Shake for 5 hours and centrifuge for 30 minutes at 4000 rpm at 5 ° C. The supernatant was taken out, and the resin component was precipitated with methanol and then dried. The resin thus obtained,
0.1 g is dissolved in toluene to make a 0.5 g / dl solution. 10 ml of this solution is placed in an Ostwald viscometer having a capillary diameter of about 0.3 mm, and the number of seconds t ₁ of the solution flowing down at 30 ° C. is measured. did. On the other hand, the number of seconds t ₀ flowing down of the toluene was measured with the same viscometer, and calculated by the following equation. At this time, the number of seconds t ₀ during which the toluene flows is about 240 seconds. η _sp / C = (t ₁ / t ₀ −1) / C (C: polymer concentration g / dl)

(3) Amount of rubbery polymer component in rubber-modified styrenic resin Nuclear magnetic resonance measuring device (UNITY 300 manufactured by Varian)
The nuclear magnetic resonance of a hydrogen atom was measured by the above method, and the amount of the rubbery polymer component was calculated from the molar ratio of the styrene unit to the butadiene unit.

(4) Deflection temperature under load (HDT), rate of decrease in deflection temperature under load The deflection temperature under load was determined by a method based on ASTM-D648 using a 1/4 inch test piece under a load of 1.81 MPa.
(18.5 Kgf / cm ² ). The rate of decrease in the deflection temperature under load is determined by measuring the deflection temperature under load x (° C.) of the rubber-modified styrenic resin used and the deflection temperature under load y (° C.) of the styrene resin composition, and Δ (xy) / x ｝ × 1
It was calculated by the formula of 00 (%).

(5) Izod Impact Strength, Izod Impact Strength Reduction Rate Izod impact strength was measured using a 1/8 inch test piece with a V notch by a method in accordance with ASTM-D256.
It measured at 60 degreeC and 60 kg. The Izod impact strength reduction rate was determined by measuring the Izod impact strength v (J / m) of the rubber-modified styrene resin used and the Izod impact strength w (J / m) of the styrene resin composition. w) /
It was calculated by the formula of v｝ × 100 (%).

The following components were used in Examples and Comparative Examples. (A) Rubber-modified styrene-based resin Reduced viscosity η _sp /C=0.63 dl / g, rubber-modified styrene-based resin having a rubbery polymer component of 4.3% by weight (hereinafter referred to as HIPS-1) Reduced viscosity η _sp /C=0.74 dl / g, 3.5% by weight of rubber-like polymer component, rubber-modified styrene resin (hereinafter referred to as HIPS-2) Reduced viscosity η _sp /C=0.96 dl / g, rubber-like weight Rubber-modified styrenic resin having a combined component content of 7.9% by weight (hereinafter referred to as HIPS-3) (B) Organophosphorus compound Diphenylpentaerythritol diphosphate {R ¹ and R ² in the general formula (1) are both phenyl groups Cyclic phosphate compound (hereinafter referred to as FR-1) triphenyl phosphate (Tachihagaku Co., Ltd.
PP (hereinafter referred to as TPP) bis (nonylphenyl) phenyl phosphate (hereinafter referred to as BNPP) produced by the following production method

Nonylphenol 287.3 parts by weight (molar ratio 2.0), magnesium chloride 0.93 parts by weight (molar ratio 0.015), phosphorus oxychloride 100 parts by weight (molar ratio 1.0) were charged, and 90 ° C. For 2 hours. Further, 61.4 parts by weight of phenol (molar ratio: 1.0) was added, the temperature was gradually raised, and the mixture was kept at 150 ° C. for 2 hours to complete the reaction.
Next, the reaction mixture was cooled and washed with water to remove the catalyst and chlorine, thereby obtaining a phosphate mixture (BNPP). This mixture was subjected to GPC (LC-10, Shimadzu Corporation).
When analyzed by AD (mobile phase tetrahydrofuran), it consisted of bis (nonylphenyl) phenyl phosphate, tris (nonylphenyl) phosphate and nonylphenyl-diphenylphosphate, and the weight ratio was 83.2 / 10.1 / 6.7. there were. The average number of carbon atoms in the substituent was 18.

[Examples 1 to 6, Comparative Examples 1 to 6] The components shown in Tables 1 and 2 were blended in a tumbler in amounts (parts by weight) shown in Tables 1 and 2, and a 15 mmφ twin screw extruder was used. The pellets were pelletized at 180 ° C. with a resin temperature (KZW15 manufactured by Technovel), and the obtained pellets were dried with a hot-air dryer at 65 ° C. for 4 hours. The dried pellets were molded at a cylinder temperature of 200 ° C. by an injection molding machine (J75Si manufactured by Nippon Steel Works, Ltd.). Tables 1 and 2 show the results of evaluation using the molded plate.

[0042]

[Table 1]

[0043]

[Table 2]

[0044]

The present invention provides a styrene-based resin composition having excellent flame retardancy, heat resistance and impact resistance. This resin composition is used for office automation equipment parts, home electric appliance parts, automobile parts. Etc. are useful as materials for molding various molded articles, and their industrial effects are outstanding.

Claims (4)

[Claims] 1. (A) Reduction measured by the method described in the text
Rubber-modified steel having a viscosity of 0.61 to 1.50 dl / g
Len-based resin (A component) and (B) in the following general formula (1)
The cyclic phosphate compound represented by at least 30
A component consisting of an organic phosphorus compound (B component) containing
The B component is 1 to 70 parts by weight with respect to 100 parts by weight.
A flame-retardant styrenic resin composition, comprising: Embedded image(Where R¹And R^TwoMay be the same or different
And a monovalent aromatic group represented by the following general formula (2).
You. )(Where Ar is a phenyl group, a naphthyl group, an anthryl
, Pyridyl and triazyl groups
Represents one group, and n is an integer of 0 to 5. R ^ThreeIs
Each may be the same or different, and on Ar
Other than the part that is bonded to phosphorus via the oxygen atom of
Moieties, methyl, ethyl, propyl
Or butyl or its linking group to Ar is oxygen,
C or carbon via an aliphatic hydrocarbon group having 1 to 4 carbon atoms
The aryl groups of the formulas 5 to 14 are shown. ) 2. The flame-retardant styrenic resin composition according to claim 1, wherein the rubber-modified styrenic resin as the component A is a resin containing a rubbery polymer component in the resin in an amount of 1 to 10% by weight. 3. The method according to claim 1, wherein the organic phosphorus compound of the component B is a cyclic phosphate compound represented by the formula (1):
An organic phosphorus compound comprising 0 to 50% by weight and 0 to 50% by weight of at least one compound selected from the group consisting of triphenyl phosphate, bis (nonylphenyl) phenyl phosphate, nonylphenyl diphenyl phosphate and tris (nonylphenyl) phosphate. The flame-retardant styrenic resin composition according to claim 1. 4. The relation between the deflection temperature under load x (° C.) of the rubber-modified styrene resin of the component A and the deflection temperature y under load of the styrene resin composition comprising the component A and the component B (° C.) The flame-retardant styrenic resin composition according to claim 1, wherein a rate of decrease in deflection temperature under load represented by (xy) / x｝ × 100 (%) is 20% or less.