JPS63183946A - Flame-retardant styrenic resin composition - Google Patents

Abstract

PURPOSE:To obtain the titled composition having excellent rigidity and dimensional accuracy while keeping impact resistance, by blending a flame-retardant styrenic resin with a specific amount of a specific inorganic filler comprising specific glass fibers, etc. CONSTITUTION:(A) 60-90wt.% flame-retardant styrenic resin obtained by blending A1: 60-90wt.% styrenic resin with A2: 10-40wt.% one or more of an inorganic flame-retardant and an organic flame-retardant (e.g. tetrabromobisphenol A, chlorinated polyethylene, etc.) is blended with (B) 10-40wt.% inorganic filler consisting of B1: 50-80wt.% glass fibers having >=20 L/D and 5-15mum fiber diameter and B2: 20-50wt.% scaly glass flakes having 1-10mum thickness and 20-500mum size.

Description

Detailed Description of the Invention (Field of Industrial Application) The present invention relates to a flame-retardant styrenic resin composition containing an inorganic filler, and more specifically, a flame-retardant resin composition that has excellent rigidity and dimensional accuracy. The present invention relates to a composition.

(Prior art and its problems) Generally, it is widely known that a highly rigid composition can be obtained by blending an inorganic flame retardant and an organic flame retardant into a resin matrix, and further mixing and filling an inorganic filler. It is well known that inorganic and organic flame retardants are used in applications where replacements for metal guicasting and sheet metal products are being considered, such as internal chassis and frames for OA equipment and office equipment. However, when a molded product made of a resin composition filled with an inorganic substance is used, the rigidity is high, but the mechanical strength, particularly the impact resistance, is low, and the dimensional accuracy of the molded product is poor, making it difficult to use in practice. there were.

Attempts to obtain a highly rigid composition include glass peas as a filler,
Although studies have been conducted using glass flakes, glass balloons, mica, talc, kaolin, silica, potassium titanate, lucium carbonate, etc., they have low impactivity and cannot be used practically; Although fibrous glass fibers, asbestos J fibers, rock wool, Kagen fibers, etc. have been studied as agents and have been put to practical use in some molded products, they are not suitable for molded products that require strict dimensional accuracy. In reality, flame retardant resin compositions that have high rigidity, practical impact resistance, and excellent dimensional accuracy have been strongly desired.

(Another Means to Solve the Problem) In view of this situation, the inventor of the present invention maintains high rigidity without reducing the impact resistance of a molded product obtained by blending an inorganic filler with a flame-retardant styrene resin. The present invention was arrived at as a result of intensive research aimed at providing a flame-retardant resin composition with improved dimensional accuracy of molded products. It has high rigidity by blending styrene resin which has been made flame retardant by blending one or more types of flame retardant and organic flame retardant with glass fiber and scaly glass flakes as inorganic fillers. This is a flame-retardant styrene resin composition that maintains practical impact resistance and has poor dimensional accuracy.

The styrenic resin used in the present invention includes, for example, styrene monomers and styrene derivatives such as α-substituted styrenes such as α-methylstyrene, para-tertiary-butylstyrene, Tsukura-methylstyrene, vinyltoluene, and nuclear-substituted styrenes such as chlorostyrene. Single or copolymers of monomers, copolymers of one or more of the styrenic monomers and other monomers, such as styrene-acrylonitrile copolymers (AS Jugeki polybutadiene copolymers with one or more of the styrenic monomers or Furthermore, graft polymers obtained by graft polymerization with other monomers, such as styrene graft polymers, styrene-acrylonitrile graft polymers (ABS resins), and those obtained by blending these styrene resins with polybutanoene rubber, etc. There are also mixtures of two or more of these resins, if necessary.

Examples of inorganic flame retardants and organic flame retardants in the present invention include tetrabromobisphenol-A1 decabromobiphenyl ether, octabromobiphenyl ether,
Bis(tribromophenoxy)ethane, ・P-chlorpentacyclodecane, hexabromo7-di-rhododecane, triphenyl phosphate, tricresyl phosphate, tributyl phosphate, tris(β-chloroethyl) phosphate, chlorinated polyethylene, antimony trioxide,
Zinc oxalate and the like can be used alone or in combination of two or more types depending on the required level of flame retardancy.

Among the inorganic fillers in the present invention, glass fiber is L/
D is 20 or more, the fiber diameter is 5 to 15 μm, and it must be treated with a silane-based binding agent during the glass fiber manufacturing process, or untreated, and the binding agent may be acrylic, urethane-based, This uses an epoxy treatment agent, etc. On the other hand, glass flakes have a scale-like shape with a thickness of 1 to 10 μm and a size of 20 to 500 μm, and are not surface-treated during the glass flake manufacturing process.

In the present invention, the above-mentioned inorganic flame retardants and organic flame retardants are used in a suitable combination depending on the level of flame retardance required to make the styrene resin flame retardant. The main ingredients of tetrabromobisphenol-A, decabromobiphenyl ether, and octabromobiphenyl ether are well combined with chlorinated polyethylene and antimony trioxide, and the blending ratio is 60 to 90% by weight of styrene resin. The flame retardant is 10 to 40 cents by weight, and preferably the styrene resin is 65 cents by weight.
~85 weight percent and 15 to 35 weight f-cents of flame retardant. If the amount of the flame retardant is less than 10 weight percent, the flame retardancy will be reduced, and if the amount of the flame retardant exceeds 40 weight percent, the impact resistance of the molded article will be significantly reduced.

In the present invention, flame retardant styrene resin 60-9
10 to 40 cents by weight of inorganic filler is added to 0 weight percent. That is, if the amount of the inorganic filler blended is less than 10% by weight, the rigidity aimed at by the present invention will be insufficient, and the rigidity will be 40% by weight! - If it exceeds cents, the molded product will become brittle and the surface smoothness will be significantly impaired.

As the above-mentioned inorganic filler, glass fibers having an L/I) of 20 or more and a fiber diameter of 5 to 15 μm and scaly glass flakes having a thickness of 1 to 10 μm and a size of 20 to 500 μm are used in combination. Although it is possible to achieve the purpose of maintaining high rigidity and practical impact resistance using glass fiber alone, blending at a high blending ratio is undesirable because it increases the warpage of the molded product and the difference in shrinkage rate. Moreover, scaly glass flakes alone are insufficient in strength. The ratio between glass fiber and scaly glass flakes is 50 to 8
0% by weight and 20 to 5 scaly glass flakes
It is 0% by weight.

Among the above inorganic fillers, the glass fibers must be short fibers with a diameter of 5 to 15 μm and an L/D of 20 or more, but fibers with an L/D of less than 20 are not effective for reinforcing styrene resin. In addition, fibers with a fiber diameter larger than 15 μm impair the appearance of the molded product, and the strength decrease rate at the weld line is large, and fibers with a fiber diameter smaller than 5 μm tend to reduce mechanical strength. The effect will also be worse.

On the other hand, if the size of the scaly glass flakes exceeds 500 μm, the appearance of the molded product will be impaired, and the rate of decrease in strength at the weld line portion will increase, which is not preferable.

The resin composition of the present invention is prepared within the above-mentioned regulation range by combining a styrene resin, a flame retardant, and glass fiber as an inorganic filler.
This is done by taking the respective glass flakes and uniformly mixing them using a V-shaped tumbler or the like according to a conventional method. The prepared composition is subjected to conventional extrusion or injection molding. In addition, when preparing the resin composition, the styrene resin is used as a part of the styrene resin, dyes and pigments, plasticizers, stabilizers, antioxidants, ultraviolet absorbers, lubricants, and other additives and inorganic fillers,
Of course, it may also contain a dispersion aid and the like used when filling.

(Example) The present invention will be explained below by giving examples.

Examples 1-4 Comparative Examples 1-4 AS resin-A (acrylonitrile-styrene copolymer-
Bound acrylonitrile 26wt%, solution viscosity 0.9ηs
p/c) and ABS resin-A (acrylonitrile-butadiene-styrene terpolymer-containing comb content: 27 wt)
%), commercially available flame retardant-A (tetrabromobisphenol-A), commercially available flame retardant-B (chlorinated polyethylene)
, commercially available flame retardant-C (antimony trioxide), commercially available glass fiber-A (diameter 11 μm, average fiber length 4 fibers, glass fiber treated with silane and acrylic sizing agent during the manufacturing process), and commercially available glass fiber. Seven components of Flake-A (average particle size: 150 mesh, average thickness: 3 μm, untreated during the manufacturing process) were thoroughly mixed in a V-type blender to obtain the composition shown in Table 1.

The obtained mixture was extruded at 210°C using a 40111111φ vent type extruder, formed into 4 pieces with a diameter of 3 to 5 mm and a length of 4 to 7 mm, and then thoroughly dried at 80°C for 3 hours or more. After that, a test piece for physical property measurement and a flat plate for mold shrinkage measurement (120X120X2+III+
A film sheet (t1) was prepared.

As for the physical properties, as listed in Table 1, the flame retardancy level is 1/16" thick and UL94V-0, and the rigidity tends to increase as the filler content increases, and it is also practical. Retains Izotsu impact strength that can be used for
The appearance and surface smoothness are good, and the difference in molding shrinkage rate between the flow direction of the resin and the direction perpendicular to it, which is an index of dimensional accuracy which is the main purpose of the present invention, is 0.2% or less. It was confirmed that this resin composition can be used in applications that require dimensional accuracy.

For comparison with the above examples, as shown in Comparative Example 1, a polymer paste containing no inorganic filler has a very small difference in molding shrinkage rate of 0.02q6, but a rigidity of 232
00 klil/cm2, which is extremely low, and when the inorganic filler is only glass fiber-A, the difference in molding shrinkage rate is 0.3
If the amount of inorganic filler exceeds 40% by weight or more, a molded product with poor appearance and surface smoothness may not be obtained.

Examples 5-9 Comparative Examples 5-7? ASit (fat-B (bonded acrylonitrile 25 wt%, solution viscosity 0.6ηsp/c
) and the same commercially available flame retardant A (tetrabromobisphenol-A
), commercially available flame retardant -C (antimony trioxide) K, new commercially available flame retardant -D (decabromo biphenyl ether)
The same commercially available glass fiber-A used in Examples 1 to 4 was used for
(diameter 11 μφ, average fiber length 4 strands, glass fiber treated with silane and acrylic sizing agent during the manufacturing process) and commercially available glass flakes-A (average particle size 150 mesh, ° average thickness 3 μm 1) 5 to 6 components of the processed product) were thoroughly mixed in a V-type blender to obtain the composition shown in Table 2, and the same method as in Examples 1 to 4 was used (however, the extrusion temperature was 230°C).
, molding temperature 2301? :) A test piece for measuring physical properties and a flat plate for measuring mold shrinkage (120×12ox2 mm, film size) were prepared.

As for the physical properties, as listed in Table 2, the flame retardancy level is 1/16" thick and UL94v-Q, and the rigidity tends to increase as the filler content increases, and it is also practical. It maintains a certain izot impact strength, has good appearance and surface smoothness, and also has low molding shrinkage in the flow direction of the resin and in the direction perpendicular to it, which is an indicator of dimensional accuracy, which is the main objective of the present invention. The difference was 0.2% or less, and it was confirmed that the resin composition could be used in applications requiring high dimensional accuracy.

In addition, in Comparative Examples 5 to 7 compared with the above examples, glass fiber
In Comparative Examples 7 and 8, in which A alone was blended, the difference in molding shrinkage rate was o.
, 28% or more, and when the glass fiber content exceeded 20 wt% as in Comparative Example 9, only molded products with poor appearance and surface smoothness were obtained.

Examples 10 to 11 Comparative Examples 8 to 11 Same AS resin-B as Examples 5 to 9 (bonded acrylonitrile 25 wt%, solution viscosity Q, 6 ηap/c) and ABS resin-B (rubber content 18 wt%, α - 45 wt% of methylstyrene), a commercially available flame retardant -C (antimony trioxide), a commercially available flame retardant -D (decabromo biphenyl ether), and the same commercially available glass fibers (diameter) used in Examples 1 to 4. 11μφ, average fiber length tetrasaccharide, glass fiber treated with silane and acrylic sizing agent during the manufacturing process)
Using commercially available Las Flake-A (average particle size 150 mesh, average thickness 3 μm, untreated product during the manufacturing process),
Furthermore, commercially available glass fiber-B (diameter 6
μφ, average fiber length 4 #, glass fiber treated with silane and acrylic sizing agent during the manufacturing process) and commercially available glass fiber -〇 (diameter 11 μφ, average fiber length 80 μm 1 treated with silane and acrylic sizing agent during the manufacturing process) processed glass fiber,
Φ = 5-6) and commercially available glass flakes-B (48 mesh sieve residue, particle size 500-2000 μm, average thickness 5
μm, untreated product during the manufacturing process) were thoroughly mixed in a V-type blender to obtain the composition shown in Table 3.
A test piece for measuring physical properties and a flat plate (120 x 120 x 2 mm, film case) for measuring mold shrinkage were prepared at 30°C.

As for the physical properties, as listed in Table 3, all of them have a flame retardant level of 1/16" thick and UL94V-0, maintain an Izot impact strength that can be used practically, and have good appearance and surface smoothness. Moreover, the difference in molding shrinkage between the flow direction of the resin and the direction perpendicular thereto, which is an index of dimensional accuracy, which is the main objective of the present invention, is 0.2% or less, and high dimensional accuracy is required. It was confirmed that the resin composition was usable for this purpose.

In addition, Comparative Examples 8 to 11 compared with the above-mentioned Examples all had a difference in molding shrinkage rate of 0.21 or less and showed high dimensional accuracy. was low, and the impact resistance showed a value that could not withstand practical use, and Comparative Example 10 was not suitable for practical use because the impact resistance decreased and the appearance deteriorated.

(Effects of the Invention) As shown above, the composition of the present invention can be subjected to extrusion molding or injection molding to obtain a molded article very easily, and the molded article can be made from conventional glass fiber reinforced flame retardant styrene. Compared to other resins, it has a better balance of physical properties, appearance, and surface smoothness, and in terms of dimensional accuracy, it has been greatly improved and is second only to metal die casting. Therefore, there is a diversity of design characteristics unique to thermoplastic resins, and since a number of parts can be molded together, it has a significant practical effect as an industrial material due to the large reduction in assembly man-hours and easy processability.

Claims (1)

[Scope of Claims] 1. 10 to 90% by weight of a styrenic resin made flame retardant by one or a combination of inorganic flame retardants and organic flame retardants; In a composition containing 40% by weight, 50 to 80% of this inorganic filler is L/
Flame-retardant styrene blended with D20 or higher, consisting of glass fibers with a fiber diameter of 5 to 15 μm, and 20 to 50% composed of scaly glass flakes with a thickness of 1 to 10 μm and a size of 20 to 500 μm. based resin composition. 2. Inorganic flame retardants and organic flame retardants include tetrabromobisphenol-A, decabromobiphenyl ether, octabromobiphenyl ether, bis(tribromophenoxy)ethane, perchloropentacyclodecane, hexabromocyclododecane, and triphenylphosphate. , tricresyl phosphate, tributyl phosphate, tris(β-chloroethyl) phosphate, chlorinated polyethylene, antimony trioxide, and zinc borate, or a combination of two or more thereof, and the blending ratio is 60 to 90% by weight of styrene resin. 2. The flame-retardant styrenic resin composition according to claim 1, wherein the inorganic flame retardant and the organic flame retardant are present in an amount of 10 to 40 percent by weight.