JPH09208768A - Flame-retardant polystyrene-based resin composition - Google Patents

Abstract

PROBLEM TO BE SOLVED: To obtain the above composition improved in flame retardancy while retaining its characteristics and generating no toxic gas when burned, by incorporating a polystyrene-based resin with a phenolic resin, a phosphorus-contg. compound and expandable graphite of low expansion degree. SOLUTION: This resin composition is obtained by incorporating (A) 100 pts.wt. of a polystyrene-based resin (pref. impact-resistant polystyrene or ABS resin) with (B) 5-30 pts.wt. of a phenolic resin (pref. phenol novolak resin), (C) 5-50 pts.wt. of a phosphorus-contg. compound (pref. red phosphorus or ammonium polyphosphate) and (D) 5-50 pts.wt. of expandable graphite <=70% in 80- mesh-on. Besides, incorporation of 5-20 pts.wt. of a nitrogen-contg. compound (esp. melamine cyanurate) in this composition results in significantly enhanced synergistic effect with both the components B and C for promoting carbonization of the composition, therefore being favorable. Specifically, this resin composition can be obtained, for example, by melt kneading of the components A-D in e.g. a pressure kneader at 150-250 deg.C for 10-30min.

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to a flame-retardant polystyrene resin composition which has excellent flame retardancy and does not generate harmful gas during combustion.

[0002]

2. Description of the Related Art Polystyrene, which is one of the typical polystyrene resins, has many advantages such as low cost, transparency, good electric insulation, good adhesion, and high rigidity. Therefore, it has a wide range of applications such as food packaging materials, household products, soft media, home appliance housings, office automation equipment, and the like. ABS resin, which is another typical polystyrene resin, has many advantages such as low cost, high rigidity, good chemical resistance, good impact resistance, and good electric insulation. Therefore, the use of general equipment, electric equipment, vehicles, miscellaneous goods, etc. is more extensive.

As described above, the polystyrene resin has various advantages, but both polystyrene and ABS resin have a common drawback that they are easily burned. As a general method for making polystyrene resin flame-retardant, it is possible to make it flame-retardant by using an organic flame-retardant agent such as an organic halogen compound and a halogenated phosphoric acid ester or a combination of these with an inorganic flame-retardant auxiliary such as antimony trioxide It is known that you can do it.
However, whichever method is adopted, the impact resistance and softening point of the resin composition are lowered, or the resin composition is extruded, and the permissible range of temperature control during injection molding is remarkably narrowed. Decompose to form colored pellets or molded products. Alternatively, there is a drawback that the effect of imparting flame retardancy disappears to an unsatisfactory level due to decomposition. Further, the use of a halogen compound has a problem of environmental destruction, although the flame retardancy is improved.

Recently, as a method of imparting flame retardancy to a polystyrene resin with non-halogen, JP-A-6-73251 is used.
It is known from Japanese Patent Laid-Open Publication No. 2003-242242 that expandable graphite containing 80% or more of red phosphorus and 80 mesh-on is used as a styrene resin. However, if expandable graphite containing 80% or more of 80 mesh on is used, the appearance during molding is significantly deteriorated, which is not practical. Further, according to JP-A-6-73251, expansive graphite having 80% mesh on and 70% has insufficient flame retardancy. As described above, in the prior art, there is no one in which expansive graphite is used and flame retardancy is improved without causing deterioration of characteristics.

[0005]

SUMMARY OF THE INVENTION It is an object of the present invention to provide a halogen-free polystyrene resin having improved flame retardancy with almost no deterioration in properties.

[0006]

[Means for Solving the Problems] As a result of the investigations by the present inventors on the non-halogen flame retardation of polystyrene resins,
It has been found that the method of simply blending the phenol resin requires a large amount of addition to improve the flame retardancy, and if the addition amount is increased, there are drawbacks such as deterioration in cold resistance and impact resistance. In addition, the same applies to the addition of phosphorus-containing compounds and nitrogen-containing compounds, in order to improve flame retardancy, it is necessary to add a large amount, and increasing the addition amount has drawbacks such as bleeding and reduction of impact resistance. There was found.

[0007] Therefore, as a result of diligent studies in order to synergistically improve flame retardancy by combining flame retardant compounds having different mechanisms, as a result, a phenol resin that forms a shell during combustion and a phosphorus-containing compound that forms a carbonized film. And when expandable graphite that expands and has a heat insulating effect is used together,
It has been found that the flame retardancy is remarkably improved even when the expansive graphite having a low degree of expansion of 80 mesh-on having a low degree of expansion of 70% or less, which cannot sufficiently obtain the effect of improving the flame retardancy by the conventional method, is used. Addition of a small amount improves flame retardancy, maintains the balance between flame retardancy and other properties, and improves flame retardancy without causing defects such as cold resistance, impact resistance, and bleeding. As a result, they have completed the present invention.

That is, the present invention is based on polystyrene resin 100.
(A) 5 to 30 parts by weight of phenolic resin, (B) 5 to 50 parts by weight of phosphorus-containing compound, and (D) 5 to parts by weight.
The present invention relates to a flame-retardant polystyrene-based resin composition, characterized in that 80 to 80 parts by weight of 80 mesh-on is mixed with 70% or less of expandable graphite, preferably to 100 parts by weight of polystyrene-based resin. , (A) 5 to 20 parts by weight of phenol novolac resin, (B) 10 to 30 parts by weight of ammonium polyphosphate, (D) 10 to 30 parts by weight of 80 mesh on and 70% or less of expandable graphite. And a flame-retardant polystyrene resin composition.

Alternatively, (A) 5 to 30 parts by weight of phenol resin, (B) to 100 parts by weight of polystyrene resin
5 to 50 parts by weight of a phosphorus-containing compound, (C) 1 to 30 parts by weight of a nitrogen-containing compound, and (D) 5 to 50 parts by weight of 80 mesh on and 70% or less of expandable graphite. The present invention relates to a flame-retardant polystyrene-based resin composition, preferably polystyrene-based resin 10
(A) 5 to 20 parts by weight of phenol novolac resin, (B) 5 to 20 parts by weight of red phosphorus, and (C) to 0 parts by weight.
5 to 20 parts by weight of melamine cyanurate, (D) 10
The present invention relates to a flame-retardant polystyrene resin composition comprising 30 parts by weight of 80 mesh on and 70% or less of expandable graphite.

(A) Phenolic resin, (B) phosphorus-containing compound and (D) expandable graphite in combination, or (A) phenolic resin, (B) phosphorus-containing compound and (C) nitrogen-containing compound and (D) expandable It has been found that when graphite is used in combination, the respective flame retardant mechanisms act synergistically to remarkably improve the flame retardancy. Therefore, even if the expansive graphite having a low expansion degree of 80 mesh-on and 70% or less is used, the flame retardancy can be improved, and the flame retardancy is remarkably improved while maintaining a good molded appearance. When phenol novolac resin with high shell-forming ability is used for phenol resin, ammonium polyphosphate having a relatively high phosphorus content for phosphorus-containing compounds and a remarkable synergistic effect with phenol resin, and expansive graphite with 80 mesh-on of 70% or less are used together. Excellent flame retardancy can be obtained while maintaining good molding appearance.

Further, a phenol novolac resin having a high shell-forming ability is used for the phenol resin, red phosphorus having the highest phosphorus content for the phosphorus-containing compound, melamine cyanurate for the nitrogen-containing compound, and expansive graphite having 80 mesh-on of 70% or less. When used together, excellent flame retardancy can be obtained while maintaining good molding appearance. Here, when the phosphorus-containing compound is red phosphorus, it is desirable to use it together with the nitrogen-containing compound. Among the nitrogen-containing compounds, melamine cyanurate having a relatively high thermal decomposition temperature is preferable.

[0012]

BEST MODE FOR CARRYING OUT THE INVENTION The polystyrene resin used in the present invention is not particularly limited and is commercially available. For example, styrene and polymers of styrene derivatives such as α-methylstyrene and vinyltoluene, and those monomers as a main component and a copolymerizable monomer such as acrylonitrile, butadiene, or isoprene with one or more copolymers. Examples include polymerized products and hydrogenated products thereof. Of these, impact-resistant polystyrene and ABS resin are preferable because they have good low-temperature impact resistance.

The phenolic resin which is the component (A) of the present invention is a very important component having a carbonization promoting function, a function of forming a shell during combustion, and a function of preventing molten droplets. The phenol resin used as the component (A) of the present invention is not particularly limited and is commercially available. For example, a phenol / formalin / formaldehyde / phenol molar ratio of 0.5 to 1. The mixture was charged in a reaction kettle at a blending ratio such that it became 0, and catalysts such as oxalic acid, hydrochloric acid, sulfuric acid, and toluenesulfonic acid were further added, followed by heating,
It can be obtained by a method in which reflux reaction is carried out for a suitable period of time, and then water separated is removed by vacuum dehydration or static dehydration, and then residual water and unreacted phenols are removed. These resins or co-condensed phenolic resins obtained by using a plurality of raw material components are used alone or in combination of two or more. Among them, a phenol novolak resin having excellent shell forming ability during combustion is preferably used.

The phosphorus-containing compound which is the component (B) of the present invention is an important component having a carbonization promoting function and a carbonized film forming function. The phosphorus-containing compound used as the component (B) of the present invention is not particularly limited and is commercially available, and examples thereof include red phosphorus, ammonium polyphosphate, melamine phosphate, phosphate ester and the like. Among them, red phosphorus and ammonium polyphosphate are preferable because of their high phosphorus content.

The nitrogen-containing compound which is the component (C) of the present invention is an important component which promotes carbonization by a synergistic effect in combination with the phenol resin and the phosphorus-containing compound. The nitrogen-containing compound used as the component (C) of the present invention is not particularly limited and is commercially available, and examples thereof include triazine compounds such as melamine and melamine cyanurate.

The expansive graphite containing 80% or less of 80 mesh on which is the component (D) of the present invention exhibits a remarkable synergistic effect when used in combination with the phenol resin as the component (A) and the phosphorus-containing compound as the component (B). It is a very important component that has the effect of expanding heat during combustion and blocking heat to significantly improve flame retardancy. The expansive graphite having 80 mesh-on of 70% or less used as the component (D) of the present invention is not particularly limited and is commercially available, and 80 mesh-on may be 70% or less by classification. It is obtained by producing expandable graphite from a graphite raw material having a small particle size.

The method for kneading the polystyrene resin composition of the present invention is not particularly limited, but as a method often used,
Polystyrene resin, (A) component phenolic resin, (B) component phosphorus-containing compound, and (D) component 80 mesh-on expandable graphite having 70% or less of 70% are added all at once, and the pressure kneader or Banbury mixer is used. 150-250 ° C, 1
A method of melt-kneading for 0 to 30 minutes, or a phenol resin as the component (A), a phosphorus-containing compound as the component (B), and expansive graphite having 80 mesh-on of 70% or less as the component (D) are preheated at 100 to 250 ° C. , After melt-kneading for 10 to 30 minutes,
It can be obtained by a method of adding to a polystyrene resin and further melt-kneading.

In the flame-retardant polystyrene resin composition of the present invention,
The (A) component phenol resin must be blended in a range of 5 to 30 parts by weight. If the amount of the phenol resin is less than 5 parts by weight, the effect of improving the flame retardancy becomes insufficient, and if it exceeds 30 parts by weight, the cold resistance and impact resistance are remarkably reduced. Among phenolic resins, phenol novolac resin is 5-20
It is preferable to blend in parts by weight in terms of shell formation during combustion and improvement of molten droplets.

The phosphorus-containing compound as the component (B) must be blended in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the polystyrene resin. If the phosphorus-containing compound content is less than 5 parts by weight, the flame retardancy-improving effect will be insufficient, and if it exceeds 50 parts by weight, bleeding will occur and mechanical properties will be markedly reduced. Among the phosphorus-containing compounds, it is preferable to add 10 to 30 parts by weight of ammonium polyphosphate because the synergistic effect of promoting carbonization with the phenol resin is remarkable. Further, it is preferable to mix 5 to 20 parts by weight of red phosphorus having the highest phosphorus content among the phosphorus-containing compounds.

The component (C), which is a nitrogen-containing compound, must be added in an amount of 1 to 30 parts by weight based on 100 parts by weight of the polystyrene resin. 1 compound containing Chisso
If it is less than 30 parts by weight, no synergistic effect with the phenol resin or phosphorus-containing compound is observed, and if it exceeds 30 parts by weight, mechanical properties and the like are markedly reduced. Among the nitrogen-containing compounds, it is preferable to add 5 to 20 parts by weight of melamine cyanurate because the synergistic effect of promoting carbonization with the phenol resin and the phosphorus-containing compound is remarkable.

The expansive graphite containing 80% mesh 80% or less of the component (D) must be added in an amount of 5 to 50 parts by weight with respect to 100 parts by weight of the polystyrene resin. If the amount of expandable graphite is less than 5 parts by weight, the effect of improving flame retardancy becomes insufficient, and if it exceeds 50 parts by weight, mechanical properties and the like are markedly reduced. The amount of expandable graphite is preferably 10 to 30 parts by weight because the flame retardancy and the mechanical properties are well balanced.
Thus, the flame-retardant polyolefin composition of the present invention,
It has the effect of improving the flame retardancy without causing the deterioration of the properties of the polystyrene resin.

The reason is that the phenolic resin as the component (A) has a function of preventing shell formation and molten droplets during combustion, and the phosphorus-containing compound as the component (B) has a synergistic effect with the phenolic resin to promote carbonization and combustion. Sometimes the function of forming a carbonized film,
The nitrogen-containing compound as the component (C) has different mechanisms such as a carbonization promoting function due to a synergistic effect with the phenol resin and the phosphorus-containing compound, and an action that the expansive graphite as the component (D) expands and insulates during combustion. It is considered that when they burn, they act synergistically to dramatically improve flame retardancy. Conventionally, when the particle size of the expansive graphite was 80% or less and the mesh size was 70% or less, the effect of improving flame retardancy was insufficient.
It has been found that the combined use of a phenol resin and a phosphorus-containing compound improves the flame retardancy even when using expandable graphite having a small particle size and a low expansion coefficient.

The flame-retardant styrenic resin composition of the present invention may further contain other compounding agents such as inorganic fillers such as talc, mica, calcium carbonate, and wollastonite, coupling agents or glass depending on the use and purpose. Fibers, reinforcing agents such as carbon fibers, inorganic hydrates such as magnesium hydroxide and aluminum hydroxide, flame retardant aids, cross-linking agents, antistatic agents, stabilizers, pigments, mold release agents, resistance to elastomers, etc. Impact modifiers and the like can be added. The flame-retardant styrene-based resin composition of the present invention can be easily processed into a molded product by a processing method used for ordinary polystyrene-based resin molded products such as injection molding and extrusion molding.

[0024]

EXAMPLES The present invention will be described below with reference to examples, but these are merely examples, and the present invention is not limited to these examples. Mechanical properties are JIS K 6874, Izod impact test is ASTM-D256, Combustion test is Underwrite
rs Laboratories Safety Standard UL94 (◯: Burning time is within 10 seconds Δ: Burning for 10 seconds or longer ×: Burnt out), and the appearance of molding is the result of visual judgment (◯: Good ×: With or without bleeding).

(Examples and Comparative Examples) As the polystyrene resin, ABS resin [ABS; ABS10 manufactured by Japan Synthetic Rubber Co., Ltd.] and polystyrene [PS; Dialex HT88 manufactured by Mitsubishi Monsanto Kasei Co., Ltd.] were used.
As the component (A), phenol novolac resin [P
N: PR-51470 manufactured by Sumitomo Dures Co., Ltd. was used. As the component (B), a phosphorus-containing compound red phosphorus [Nova Excel 140 manufactured by Rin Kagaku Kogyo Co., Ltd.], ammonium polyphosphate [Sumisafe; Sumisafe P manufactured by Sumitomo Chemical Co., Ltd.], melamine phosphate [MPP-A; MPP-A manufactured by Sanwa Chemical Co., Ltd. was used. As the component (C), melamine cyanurate [MC-410; manufactured by Nissan Chemical Industries, Ltd. MC-410] and melamine were used. As the component (D), expandable graphite obtained by classifying commercially available expandable graphite
(80 mesh on was 65%) and expansive graphite (80 mesh on was 80%). Further, in the examples of the present invention, (A) phenol resin, polystyrene resin,
A method was used in which the phosphorus-containing compound (B) and / or the nitrogen-containing compound (C) and the expansive graphite (D) were added all at once and melt-kneaded.

[0026]

[Table 1]

[0027]

[Table 2]

[0028]

[Table 3] As is apparent from the table, the polystyrene-based resin composition of the present invention is a non-halogen flame-retardant polystyrene-based resin composition that can be obtained as a molded product having both mechanical properties and flame retardancy.

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Claims (2)

[Claims] 1. A phenol resin of 5 to 30 parts by weight (A), and 5 parts by weight of (B) with respect to 100 parts by weight of a polystyrene resin.
A flame-retardant polystyrene-based resin composition comprising: ~ 50 parts by weight of a phosphorus-containing compound, and (D) 5 to 50 parts by weight of 80 mesh-on and 70% or less of expandable graphite. 2. (A) 5 to 30 parts by weight of phenol resin, (B) 5 to 100 parts by weight of polystyrene resin.
To 50 parts by weight of a phosphorus-containing compound, (C) 1 to 30 parts by weight of a nitrogen-containing compound, and (D) 5 to 50 parts by weight of 80% mesh-on expandable graphite of 70% or less. Flame-retardant polystyrene resin composition.