KR960015113B1 - Flame retardant thermoplastic resin composition - Google Patents

Abstract

The nonflammable thermoplastic resin is composed of 100 wt% the mixture of polycarbonate and acrylonitrile-butadiene-styrene copolymer, 1-15 wt% phosphorus based flame retardant such as bis(1,3-phenylene-diphenyl)(tri)phosphate, 1-16 wt% nitrogen compound expressed as structural formula (I) where X is R1-NH, R1 is H, alkyl or cycloalkyl, R2 is divalent piperazine radical, n is 20-50, or 2-20 wt% low melting point(300-500 deg.C) glaze such as zinc borate.

Description

Flame Retardant Thermoplastic Composition

The present invention relates to a thermoplastic resin composition, and more particularly, to a composition of a polycarbonate (hereinafter referred to as "PC") / acrylonitrile-butadiene-styrene (hereinafter referred to as "ABS") copolymer mixture having improved flame retardancy. will be.

Conventional flame retardant techniques for plastics generally employ bromine compounds or chlorine compounds. This technique can achieve excellent flame retardancy, but has problems such as generation of toxic gas and corrosion of metal.

In the case of using a flame retardant of the phosphorus compound can solve the above problems, the phosphorus-based flame retardant has a problem that the polymer to be applied is very limited. That is, polymers that can be flame retarded with phosphorus-based flame retardants are polymers that vary depending on the type of flame retardant, but generally have a chemical structure that enables effective dehydration of phosphoric acid or leave a considerable amount of non-combustible carbon residue (char) upon thermal decomposition. . Examples thereof include cellulose, derivatives thereof, polyurethane, polyester, and the like.

Phosphorus-based flame retardants used in these are usually phosphate esters (phosphates), which are converted to metapolyphosphoric acid when burning plastics, which causes dehydration to separate hydrogenated oxygen atoms from polymers, thereby forming a large amount of non-combustible chars. In addition, it forms a heat-insulating carbon protective film to block the oxygen from the plastic and air, and protects the plastic from the heat from the flame to show the flame retardant effect.

During the flame-retardation process as described above, before the char is formed by the action of phosphoric acid, cutting of the main chain of the polymer is preceded, thereby lowering the viscosity of the burned plastic melt, which may cause dripping. Therefore, there is a need for a method of preventing dripping by increasing the viscosity of the molten plastic during combustion, and there is room for improvement because the material used therein is fluorine resin, but it is expensive and may degrade workability.

Phosphoric acid ester-based flame retardants known so far are those that are liquid or have a melting point of 100 degrees Celsius or less, and most of them have plasticity and thus have a disadvantage of lowering heat resistance of plastics. Therefore, when used in the PC and ABS copolymer composition will lower the heat deformation temperature.

The present invention is to solve the above-mentioned problems, it is an object of the present invention to provide a PC / ABS copolymer composition that prevents the drooping phenomenon, there is no degradation in processability and heat resistance.

In order to achieve the above object, the present inventors found that the phosphorus-based flame retardant is used as a flame retardant, but the addition of nitrogen compound and / or low melting glaze minimizes the decrease in heat resistance of the PC / ABS copolymer.

That is, the present invention is 1 to 15 parts phosphorus-based flame retardant with respect to 100 parts by weight of the PC / ABS mixture (hereinafter abbreviated as "part"), 1 to 16 parts of nitrogen compound having a structure as shown in the following structural formula (1) and / Or 2 to 20 parts of a low melting glaze.

[Formula 1]

Wherein X = R ₁ -NH, R ₁ = H alkyl or cycloalkyl, R ₂ = divalent piperazine radical, an integer from n = 20 to 50.

Hereinafter, the present invention will be described in detail.

The PC / ABS mixture used in the present invention has a weight ratio of PC: ABS of 5-8: 2-5, preferably 6-8: 4-2.

Phosphorus-based flame retardants that can be used in the present invention are bis (1,3-phenylene-diphenyl) phosphate, triphenylphosphate, triarylphosphate or tricresylphosphate and the like, more preferably bis (1,3-phenylene- Diphenyl) phosphate and triphenyl phosphate. In addition, when a low melting inorganic glaze is used together, a more rigid nonflammable film is formed. The appropriate amount of use is 1 to 15 parts per 100 parts of resin, and when less than 1 part, the heat resistance effect is insufficient, and when the amount exceeds 15 parts, physical properties decrease.

The low melting glaze used in the present invention has a melting point of 300 ° C to 500 ° C, which melts at the combustion temperature of the plastic when it is burned, thereby increasing the viscosity of the plastic melt to prevent dripping and at the same time forming a glassy film. It plays the same role as formation. The appropriate usage amount is 2-20 parts with respect to 100 parts of resin. If it is less than 2 parts, there is a lack of anti-dripping effect, and if it is more than 20 parts, fluidity and impact strength are deteriorated.

As the low melting glaze, zinc borate having a water content of 30% by weight or less is used.

On the other hand, in order to further increase the heat resistance, it is possible to apply nitrogen compounds (hereinafter referred to as "Compound A") having a structure as shown in the following structural formula (I). Compound A serves to strengthen the carbon protective film formed during combustion. The usage-amount is 1-16 parts with respect to 100 parts of resin. If it is less than 1 part, there is a problem that there is no non-combustible film reinforcement function at all, and if it exceeds 16 parts, there is a problem that gas silver phenomenon occurs in the appearance during injection.

Specific examples of the compound "A" include 1,3,5-triazine-piperazine oligomer, wherein X is an amine, and the same amount of nitrogen compound as isocyanurate derivative and melamine derivative is used instead of compound A. Can be used as

Another advantage that can be obtained by using the nitrogen compound or low melting glaze is that the desired flame retardancy can be obtained even if the content of the PC is reduced. ABS component hardly leaves any residue or char when it is pyrolyzed, but PC leaves about 20-30% of the initial weight of the char. Therefore, if the mixture of PC and ABS copolymer is flame retardant with conventional phosphorus-based flame retardant, The flame retardancy is increased. Therefore, blends with a high proportion of PCs, which are relatively expensive polymers, must be used. However, the addition of low-melting glazes or nitrogen compounds, which can form the above-mentioned film, can reduce the content of PCs. It enhances the film-forming ability of the various blends of physical properties can be made.

Embodiments of the present invention are as follows.

[Examples 1-6 and Comparative Examples 1-3]

The mixing ratios of Examples and Comparative Examples are shown in Table 1 below, and each sample was mixed by a Henschel mixer for 10 minutes and then melt mixed in a twin screw extruder. Flame retardancy was measured by UL-94 flame retardancy test for 1/8 inch thickness.

Legend)

1) Phosphorus Compound 1: Bis (1,3-phenylene-diphenyl) phosphate

2) Phosphorus Compound 2: Triphenyl Phosphate

3) Nitrogen Compound 1: Triphenylisocyanurate

4) Nitrogen Compound 2 (Compound A): 1,3,5-triazine-piperazine oligomer wherein X is an amine

5) Low melting glaze: zinc borate with water content of 20% by weight

6) Whether dripping: ○: Occurrence, ×: No

In Examples 1 to 3, when a bis (1,3-phenylene-diphenyl) phosphate was used, a nitrogen compound and a low melting point glaze were applied. Compared with Comparative Examples 1 and 2, the presence or absence of a nitrogen compound and a glaze Even if the same phosphorus compound is used, it can be seen that there is a difference in flame retardancy.

In addition, as can be seen in Comparative Example 3, when triphenyl phosphate alone is used in excess of phosphorus compound 1 to obtain flame retardancy, the heat distortion temperature is significantly lowered as a result.

Claims (5)

1 to 15 parts by weight of a phosphorus flame retardant, 100 parts by weight of a mixture of a polycarbonate and an acrylonitrile-butadiene-styrene copolymer, and 1 to 16 parts by weight of a nitrogen compound having a structure such as the following structural formula (1) and / or a low melting point Flame retardant thermoplastic resin composition characterized in that it contains 2 to 20 parts by weight of glaze. [Formula 1] Wherein X = R ₁ -NH, R ₁ = H alkyl or cycloalkyl, R ₂ = divalent piperazine radical, an integer from n = 20 to 50. The flame retardant thermoplastic resin composition according to claim 1, wherein the weight ratio of polycarbonate and acrylonitrile-butadiene-styrene in the copolymer mixture is 5-8: 2-5. The flame retardant thermoplastic resin composition of claim 1, wherein the phosphorus-based flame retardant is one selected from bis (1,3-phenylene-diphenyl) phosphate or triphenylphosphate. The flame retardant thermoplastic resin composition according to claim 1, wherein the melting point of the low melting glaze is 300 to 500 ° C. The flame retardant thermoplastic resin composition according to claim 1 or 4, wherein a zinc borate having a water content of 30 wt% or less is used as the low melting glaze.