JPH05170996A - Flame-retardant acrylic resin composition - Google Patents

Abstract

PURPOSE:To obtain the subject resin composition consisting of an acrylic resin and a specific polyphosphate compound, having high flame retardancy and causing no lowering of mechanical strength and softening point, free from coloration and suitable for electric and electronic parts, automobile parts, building materials, etc. CONSTITUTION:The objective flame-retardant acrylic resin composition having high flame retardancy, causing no lowering of mechanical strength and lowering of softening point and free from coloration is obtained by blending (A) an acrylic resin such as methacryl resin with (B) a flame retardant consisting of a polyphosphate compound expressed by formula I [R<1> to R<4> are phenyl or groups of formula II, formula III, etc.; (n) is 1-5] (e.g. phenyl- credylhydroquinonepolyphosphate) with a mixer and subjecting the blend to flat plate extrusion with 40 mm extruder equipped with T die at 250 deg.C and forming a molding consisting of extruded sheet, etc., through three polishing rolls heated to about 100 deg.C.

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION The present invention relates to an acrylic resin composition having excellent flame retardancy. Specifically, it relates to a flame-retardant composition in which a polyphosphate compound is mixed with an acrylic resin.

[0002]

Acrylic resins are excellent in optical properties, mechanical properties, water resistance, chemical resistance and electrical insulation properties and, in addition, they are easy to mold and process. Widely used as automobile materials and sundries. However, acrylic resins have a drawback that they are relatively easy to burn among synthetic resins. For this reason, a method has been proposed in which an acrylic resin is added with a flame retardant to make it flame-retardant, like other combustible resins. For example, flame retardation of polymers-Chemistry and actual technology- <Enlarged new edition> Published by Taiseisha Co., Ltd. on February 28, 1987, was published as a flame retardant for acrylic resins, such as organic chlorine compounds, phosphate esters, triester Organic phosphorous compounds such as cresyl phosphate are described.

[0003]

Acrylic resins, which have a relatively high flammability, require a large amount of flame retardant, and depending on the type, decrease the mechanical strength and softening point of the resin, At the time of molding, the compound is decomposed and the resin is easily colored, and thus various excellent properties represented by the acrylic resin such as light transmittance are easily lost. Therefore, effective flame retardants for other resins are not always suitable, and flame retardants suitable for acrylic resins are desired.

[0004]

The present invention provides a flame-retardant acrylic resin composition comprising an acrylic resin and a polyphosphate compound represented by the following formula (2).

[0005]

[Chemical 2]

In the formula, R ¹ , R ² , R ³ and R ⁴ are one of those shown in the following [External 2].

[Outside 2]

As the acrylic resin in the present invention,
It is a well-known polymer mainly composed of methyl methacrylate,
As the copolymerization component, there are (meth) acrylic acid ester, (meth) acrylic acid, styrene, α-methylstyrene, acrylonitrile, maleic anhydride, glutaric anhydride, glutarimide, and the like. Those reinforced with polymers or elastomers such as acrylic rubber and butadiene rubber are applicable.

The polyphosphate compound of the present invention includes a known method for producing a polyphosphate compound, for example, the method described in JP-A No. 63-227632, and resorcinol, hydroquinone, catechol, dihydroxybenzenes. And phosphorus oxychloride are reacted with each other, and then phenols constituting R ¹ , R ² , R ³ and R ⁴ in the formula are reacted with each other to produce the compound.

R ¹ , R ² , R ³ and R ⁴ may be the same or different. Repeating unit n is 1 to 5, preferably 1 to
It is 3. If n is too large, the viscosity becomes high and the physical properties of the resin composition are adversely affected.

The content of the polyphosphate compound is 0.5 to 40% by weight, preferably 1 to 1 based on the total composition.
It is 5% by weight. If it is less than this range, a sufficient flame retardant effect cannot be obtained, and if the content is more than this range, the physical properties of the acrylic resin composition, particularly the strength, are reduced.

The flame-retardant acrylic resin composition of the present invention comprises
At the time of producing the acrylic resin, known antioxidants, lubricants, colorants, weathering agents and the like which are usually used may be added.

The flame-retardant acrylic resin composition of the present invention comprises
The predetermined components can be mechanically mixed by a Henschel mixer, a tabler or the like, and melt-kneaded by a Banbury mixer or a single-screw or twin-screw extruder. The composition thus obtained can be shaped into a product by injection molding or extrusion molding. Further, the phosphate compound represented by the formula (1) may be mixed and dispersed in the monomer or syrup of the acrylic resin and polymerized. Cast polymerization, which is carried out in a mold, gives a shaped composition.

[0013]

The flame-retardant acrylic resin composition of the present invention has excellent flame retardancy while maintaining the optical and mechanical properties that the acrylic resin originally has. This is useful for applications such as electronic and electrical parts, OA equipment parts, automobile parts, building materials, signboards, and glazing materials that require flame retardancy.

[0014]

EXAMPLES The flame retardants used in the examples are as follows. -Flame retardant A: Phenyl cresyl hydroquinone polyphosphate-Flame retardant B: Tetrabiphenyl hydroquinone polyphosphate-Flame retardant C: Triphenyl phosphate-Flame retardant D: Tricresyl phosphate

The evaluation method is as follows. Flame retardance: Based on the UL94HB (JIS K6911C) combustion test method, a UL-94HB type flammability tester manufactured by Suga Test Instruments was used to evaluate the burning rate. -Heat distortion temperature: Measured using a 148-HDR heat distortion tester manufactured by Yasuda Seiki Co., Ltd. according to ASTM-D648. -Coloring: According to JIS-K7103, a plate-like sample having a thickness of 3 mm and a length of 5 cm in both length and width was measured for yellowness (YI) using an SZ-Σ80 spectroscopic color difference meter manufactured by Nippon Denshoku Industries Co., Ltd. Bleedability: The presence or absence of bleeding was observed by visually observing the surface state of the plate-shaped sample after leaving it in a constant temperature room of 23 ° C. and 50% RM for 10 days. Those that did not exist were marked with ◯, and those that existed were marked with x.

Examples 1 to 10 Methacrylic resin (SUMIPEX Ex Sumitomo Chemical Co., Ltd.)
And a flame retardant and their amounts shown in Table 1 were blended in a mixer, and then flat-plate extruded at a temperature of 250 ° C. by a 40 mm extruder with a T-die (manufactured by Tanabe Plastic Co., Ltd.).
An extruded plate having a thickness of 3 mm was obtained via three polishing rolls at about 0 ° C. This extruded plate was evaluated. The results are shown in Table 1.

[0017]

[Table 1]

Comparative Examples 1 to 9 The same procedure as in Example 1 was carried out except that the flame retardant and its amount shown in Table 2 were used. The results are shown in Table 2.

[0019]

[Table 2]

Claims (1)

[Claims] 1. A flame-retardant acrylic resin composition comprising an acrylic resin and a polyphosphate compound represented by the following [Chemical formula 1]. [Chemical 1] In the formula, R ¹ , R ² , R ³ and R ⁴ are ones shown in [External 1] below. [Outer 1]