JPS63191852A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To provide a flame-retardant resin compsn. which has excellent processability, impact resistance and resin replaceability in molding machines and is excellent in general physical properties, consisting of a vinyl chloride resin and a specified ABS resin. CONSTITUTION:A flame-retardant resin compsn. consists of 30-80pts. (by weight; the same applies hereinbelow) vinyl chloride resin (A) having an average degree of polymn. of 300-1,000 and 70-20pts. ABS resin (B). 100pts. ABS resin of the component B is composed of 50-80pts. styrene copolymer (a) and 50-20pts. graft copolymer (b) wherein the component (a) is mainly composed of a styrene compd. monomer and a vinyl cyanide compd. monomer and has a number-average MW of 20,000-40,000 and the component (b) is obtd. by copolymerizing at least 50% conjugated diene rubber with not more than 50% vinyl monomer selected from the group consisting of a vinyl cyanide compd. and an arom. vinyl compd. By using the resins A and B having a relatively low MW, a resin compsn. which has excellent processability, impact resistance and resin replaceability in molding machines, is excellent in general physical properties and causes neither scorching nor discoloration can be obtd.

Description

DETAILED DESCRIPTION OF THE INVENTION The present invention relates to a flame-retardant resin composition, and more specifically, it is composed of a vinyl chloride resin and an ABS resin, and has excellent processability, impact resistance, and resistance in a molding machine. The present invention relates to a flame-retardant resin composition with excellent resin substitution properties.

Conventional Rubber polymers such as ABS resin have excellent impact resistance, heat resistance, and processability, and are also well-balanced in other properties, so they are used for electrical equipment parts, automobile parts, Widely used for building materials, etc. However, in recent years, high flame retardancy has been required to ensure safety in the event of fire in these applications.

Generally, in order to make ABS resin flame retardant, there are two methods: adding and mixing flame retardants such as antimony dioxide, halogen-containing compounds, or phosphorus-containing compounds to ABS resin, and mixing a self-extinguishing resin with ABS resin. A method of making a so-called resin alloy is known. However, the former method requires the addition of a large amount of flame retardant, which deteriorates the mechanical properties, heat resistance, weather resistance, etc. of the resin, and also poses problems in safety, health, and economy. In the latter method, an alloy molded article is obtained by kneading ABS resin and vinyl chloride resin using a Banbury mixer or the like, and then using a method such as injection molding. When using this method, since the viscosity of ABS resin is high, it is necessary to set the processing temperature to a temperature almost close to the decomposition temperature of the vinyl chloride resin, resulting in a problem with the thermal stability of the vinyl chloride resin. In particular, when alloy molded products are obtained using an injection molding machine, the molten resin sticks to the metal surfaces of the molding machine's cylinder, screw, nozzle, etc., causing partial retention, resulting in resin burns and thermal discoloration of the molded product. ,Here,
Resin burns significantly impair the commercial value of molded products.

Therefore, various methods have been proposed to solve the above-mentioned problems in the production of flame-retardant resin compositions made of ABS resin and vinyl chloride resin. For example, a method using a vinyl chloride resin with a small molecular weight has been proposed, but when using this method, it is difficult to obtain practical mechanical strength and thermal stability.
There is a natural limit to the molecular weight of the vinyl chloride resin used. A method of adding a large amount of plasticizer or lubricant to a resin mixture is also known, but when this method is used, these additives may bleed onto the surface of the molded product or a peeling phenomenon may occur in the molded product.

JP-A-57-14638 discloses that by coexisting as a latex a polymer containing alkyl acrylate or alkyl methacrylate as a main component during the production of ABS resin, the melt viscosity of the resulting ABS resin is lowered and the heat resistance is improved. An improvement method has been proposed, but this method increases the number of steps and raw material costs, so as an industrial method for manufacturing ABS resin,
There are disadvantages in terms of economy.

Furthermore, JP-A No. 53-39346 discloses a product in which a relatively low molecular weight styrene resin is mixed with a relatively low molecular weight vinyl chloride resin and an ethylene-vinyl acetate copolymer resin to improve thermal fluidity. Enriched compositions have been proposed. However, low-molecular-weight styrene resins also reduce the mechanical strength and heat resistance of the resin composition, so there is a natural limit to the amount of styrene resins that can be blended. There are also limits.

The inventors of the present invention have conducted intensive research to solve the above-mentioned problems in flame-retardant ABS resin compositions. During injection molding of ABS resin compositions, thermal deterioration such as resin burning and resin discoloration that occurs due to partial retention of the resin composition is caused by the structure of the vinyl chloride resin as well as the amount of ABS resin blended in the resin composition. It is significantly affected by molecular weight, and by optimizing these, it is possible to expand the moldable temperature range and prevent resin burn and discoloration without deteriorating general physical properties such as heat resistance. This discovery led to the present invention.

Therefore, an object of the present invention is to provide a flame-retardant ABS resin composition that is free from resin burning and resin discoloration and has excellent film properties.

The flame retardant resin composition according to the present invention for solving the problem of
It is characterized by comprising 30 to 80 parts by weight of 1000 vinyl chloride resin (a) and 70 to 20 parts by weight of ABS resin (b).

In the present invention, the vinyl chloride resin (a) refers to polyvinyl chloride and a monomer having an ethylenically unsaturated bond that is copolymerizable with 90% by weight or more of vinyl chloride.
0% by weight or less, preferably 5% by weight or less. Examples of the monomer having an ethylenically unsaturated bond include α-olefins such as ethylene and propylene, alkyl vinyl esters such as vinyl acetate, vinylidene halides such as vinylidene chloride, vinyl cyanides such as acrylonitrile, and methyl acrylate. , acrylic acid and methacrylic acid alkyl esters such as methyl methacrylate, and alkyl vinyl ethers such as methyl vinyl ether, but are not limited thereto.

In the present invention, the vinyl chloride resin needs to have an average degree of polymerization in the range of 300 to 1000 in order for the desired resin composition to have excellent thermal stability and processability. In the resin composition according to the present invention, such a vinyl chloride resin is used as ABS resin 70 to 20, which will be described later.
It is blended in a range of 30 to 80 parts by weight. When the amount of vinyl chloride resin is less than 30 parts by weight, the desired flame retardance cannot be obtained, and when it exceeds 80 parts by weight, the impact resistance and thermal stability are significantly reduced.

The vinyl chloride resin used in the present invention may be produced by any of conventional methods such as suspension polymerization, emulsion polymerization, and bulk polymerization.

In the present invention, the ABS resin (b) consists of a styrene copolymer (c) and a graft copolymer (d).

The above-mentioned styrene-based copolymer (c1 refers to a copolymer having a styrene-based compound and a vinyl cyanide compound as the main monomer components; examples of the styrene-based compound include styrene, α-methylstyrene, etc.) Also, as the vinyl cyanide compound, for example, acrylonitrile is suitably used.In this copolymer (c), the styrene compound is 60 to 90% by weight, and the vinyl cyanide compound is 40 to 10% by weight. %, but if necessary, alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate, and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate may also be used as monomer components. The styrenic copolymer (c) may be included in the copolymer (c1) within a range of % by weight or less. α- as a styrenic compound
Preferably, it consists of 65-80% by weight of methylstyrene and 35-20% by weight of acrylonitrile as a vinyl cyanide compound.

Furthermore, in the present invention, the number average molecular weight of the styrenic copolymer (c1) must be in the range of 20,000 to 40,000. If the number average molecular weight is less than 20,000, the resulting resin composition If the heat resistance is insufficient and on the other hand exceeds 40,000, resin burn and thermal discoloration occur during molding, making it impossible to obtain injection molded products of excellent quality.

In the resin composition according to the present invention, 100 parts by weight of the ABS resin preferably comprises 150 to 80 parts by weight of the above styrene copolymer (c) and 50 to 20 parts by weight of the graft copolymer (d) described below.ABS When the amount of the styrene copolymer is less than 50 parts by weight in 100 parts by weight of the resin, resin burning and resin coloring occur in the resulting resin composition, and the heat resistance also decreases, which is undesirable.
If the amount exceeds 0 parts by weight, the resulting resin composition will have significantly poor impact resistance.

The above styrenic copolymer (c) may be produced by any of ordinary emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization, and may be produced by any of ordinary emulsion polymerization, suspension polymerization, solution polymerization, and bulk polymerization. By using an appropriate amount of dimer etc., it is possible to produce a product having a desired molecular weight.

In the present invention, the graft copolymer (d) contains 50% by weight or more of a conjugated diene rubber made of polybutadiene, polyisoprene, or a mixture thereof, and at least one kind selected from vinyl cyanide compounds and aromatic vinyl compounds. It is a graft copolymer made by copolymerizing 50% by weight or less of a vinyl monomer.

In this graft copolymer, when the vinyl monomer component exceeds 50% by weight, the amount of the conjugated diene rubber component is insufficient and the resulting resin composition does not have satisfactory impact resistance.

As the conjugated diene rubber, polybutadiene is particularly preferably used, and as the vinyl cyanide compound,
In particular, acrylonitrile is preferably used, and as the aromatic vinyl compound, for example, styrene, α-methylstyrene, etc. are preferably used. If necessary, alkyl acrylates such as methyl acrylate, ethyl acrylate, and butyl acrylate, and alkyl methacrylates such as methyl methacrylate, ethyl methacrylate, and butyl methacrylate may also be copolymerized as monomer components in an amount of 30% by weight or less. May be included in the combination. This graft copolymer (d) is blended in an amount of 20 to 50 parts by weight in 100 parts by weight of the ABS resin.

This graft copolymer can also be produced by ordinary emulsion polymerization, suspension polymerization,
It may be produced by either bulk polymerization.

The resin composition according to the present invention can be produced by conventional methods known in the art for producing flame-retardant ABS resin compositions. Therefore, for example, predetermined amounts of each of the above-mentioned vinyl chloride resin, styrene copolymer, and conjugated diene rubber graft copolymer are added together with stabilizers, lubricants, processing aids, pigments, fillers, etc. as necessary. mix,
For example, it can be obtained by kneading with an extruder, Banbury mixer 1 kneading roll, etc., and forming it into pellets. Incidentally, as the stabilizer, a tin-based stabilizer or a lead-based stabilizer is preferable.

Furthermore, as mentioned above, the flame-retardant ABS resin composition of the present invention contains a relatively low-molecular-weight styrene-based copolymer as well as a relatively low-molecular-weight vinyl chloride-based resin, and therefore has good processability. , has excellent impact resistance and resin replacement property in the molding machine, and also has excellent film properties. In particular, it has been known that when the molecular weight of the so-called rigid component, that is, the styrene copolymer, in AB'S resin is set to 4000 or less, the general physical properties of the resulting resin composition are significantly reduced. According to the present invention, by forming a polymer alloy together with a vinyl chloride resin, the physical properties of the film are maintained in a well-balanced manner, and in particular, resin burning and resin discoloration do not occur.

Garage M The present invention will be described below with reference to Examples, but the present invention is not limited to these Examples in any way.

Example 1 170 parts by weight of distilled water, 2.5 parts by weight of disproportionated rosinate, 0.3 parts by weight of potassium persulfate, t
-2.0 parts by weight of dodecyl mercaptan, 26 parts by weight of acrylonitrile, and 74 parts by weight of α-methylstyrene were charged and polymerized at 70°C for 4 hours. The obtained latex was coagulated, washed, and dried to obtain a styrenic copolymer (c1-1) with a number average molecular weight of 21,000. The polymerization conversion rate was 93%.
Met.

Separately, in a reaction vessel equipped with a stirrer, 200 parts by weight of distilled water, 1.3 parts by weight of disproportionated rosinate, 0.3 parts by weight of potassium persulfate, 65 parts by weight of polybutadiene, and 10 parts by weight of acrylonitrile.
．． 5 parts by weight and 24.5 parts by weight of styrene, 70
Polymerization was carried out at ℃ for 3 hours. The obtained latex is coagulated, washed, and dried to form a polybutadiene graft copolymer (d).
The zero polymerization conversion rate at which -1 was obtained was 95%.

30 parts by weight of the above styrene copolymer, 20 parts by weight of the polybutadiene graft copolymer, and polyvinyl chloride with an average degree of polymerization of 450 (Sumilit 5X-4 manufactured by Juju Chemical Industry Co., Ltd.)
G) 50 parts by weight were powder-mixed with 3.7 parts by weight of dibutyltin maleate, 1.0 parts by weight of organic tin mercaptide and 1.0 parts by weight of calcium stearate, kneaded in a Banbury mixer, and pelletized. This pellet was molded using a 2-ounce injection molding machine with a cylinder temperature of 230°C.

Example 2 In the production of the styrenic copolymer of Example 1, polymerization conditions were used in which the amount of t-dodecyl mercaptan used was varied as shown in Table 1, but in the same manner as in Example 1. Styrenic copolymer with a number average molecular weight of 37,000 (c1
-2 was produced, and using this, a pellet was produced in the same manner as in Example 1, and molded using an injection molding machine.

Comparative Examples 1 and 2 In the production of the styrenic copolymer of Example 1, the same procedure as Example 1 was used except that the amount of t-dodecyl mercaptan used was varied as shown in Table 1. to produce styrenic copolymers (c)-3 and (c)-4 with number average molecular weights of 16,000 and 65,000, respectively,
Using this, pellets were produced in the same manner as in Example 1, and molded using an injection molding machine.

Comparative Examples 3 and 4 Example 2 except that the blending amounts of graft copolymer (d)-1, styrene copolymer (0)-2, and vinyl chloride resin were varied as shown in Table 2. Pellets were produced in the same manner as in Example 2, and molded using an injection molding machine.

Comparative Examples 5 and 6 Same as Example 2 except that the blending amounts of the graft copolymer (d+-1 and styrene copolymer (e)-2) were varied as shown in Table 2. Pellets were produced and molded using an injection molding machine.

Comparative Example 7 A polybutadiene graft was produced in the same manner as in Example 1, except that the amount of polybutadiene used was varied as shown in Table 1 in the production of graft copolymer (d)-1. Copolymer td)-2 was produced. The polymerization conversion rate was 94%.

Using this, pellets were produced in the same manner as in Example 2, and molded using an injection molding machine.

The physical properties of the resin composition according to the present invention and the resin composition as a comparative example obtained as described above were measured. The results are shown in Table 2.

The method for measuring physical properties is as follows.

The number average molecular weight of the styrene copolymer was determined by calculation from a standard polystyrene calibration curve using C, PC (HLC-802A manufactured by Toyo Soda Kogyo ■).

Notched Izot impact value According to 8STM D 256.

heat distortion temperature According to ASTM D 648-56.

Tensile strength According to ASTM D638.

bending strength According to ASTM 0790.

Braminder decomposition time Fill the Brabender Plastograph with 50g of resin,
The torque was recorded under the conditions of 30° C. and 70 rotations, and the time (minutes) required for the torque to rise was determined.

Resin burn and resin discoloration A cylinder with a width of 2 in a 2 oz injection molding machine at a temperature of 230°C.
Molding a molded body of 5 m1, thickness 3 fl, and length 80 m,
Evaluation was made visually. As for the evaluation criteria, O indicates that there is no resin burning or resin discoloration, × indicates that there is resin burning or resin discoloration, and XX indicates that both resin burning and resin discoloration are significant.

A flame retardant sample with a thickness of 1/8 inch was used and UL-94 method was followed.

According to the resin composition of the present invention, there is no resin burning or resin discoloration, and the physical properties of the film are well balanced.

In particular, it has excellent notched isot impact value and heat distortion temperature.

On the other hand, the resin composition according to Comparative Example 1 has a low graininess due to the small number average molecular weight of the styrene polymer, and is particularly poor in notched Izot impact value and heat distortion temperature.

On the other hand, the resin composition according to Comparative Example 2 has a high number average molecular weight of the styrene copolymer, so although it has excellent -grain properties, it suffers from resin burn and resin discoloration, and has no commercial value.

Furthermore, when the blending ratio of ABS resin and vinyl chloride resin is varied, when the vinyl chloride resin is less than 30 parts by weight, as shown in Comparative Example 3, the resulting resin composition does not meet the target difficulty. Flammability cannot be ensured, and on the other hand, when the amount exceeds 80 parts by weight, as shown in Comparative Example 4, the resulting resin composition is significantly inferior in impact resistance, heat resistance, and thermal stability.

When the blending ratio of the graft copolymer and the styrene copolymer is varied, when the graft copolymer (d)-1 exceeds 50 parts by weight out of 100 parts by weight of the ABS resin, the results are shown in Comparative Example 5. As shown in Comparative Example 6, when the resulting resin composition has poor heat resistance and thermal stability and is less than 20 parts by weight, the resulting resin composition may not have satisfactory impact resistance. do not have.

In addition, when using a polybutadiene graft copolymer (dl-2) in which the polybutadiene content in the graft copolymer is less than 50% by weight, as shown in Comparative Example 7, the resulting resin composition is Does not have satisfactory impact resistance.

Claims (4)

[Claims] (1) 30 to 80 parts by weight of vinyl chloride resin (a) with an average degree of polymerization of 300 to 1000 and 70 to 20 parts by weight of ABS resin (b)
A flame-retardant resin composition comprising parts by weight. (2) 100 parts by weight of ABS resin (b) is 50 to 80 parts by weight of styrenic copolymer (c) and graft copolymer (d)
50 to 20 parts by weight of the flame-retardant resin composition according to claim 1. (3) The styrenic copolymer (c) has a styrene compound and a vinyl cyanide compound as main monomer components, and has a number average molecular weight in the range of 20,000 to 40,000. The flame-retardant resin composition according to scope 2. (4) Graft copolymer (d) is conjugated diene rubber 50
50% by weight or more, and at least one vinyl monomer selected from vinyl cyanide compounds and aromatic vinyl compounds.
The flame-retardant resin composition according to claim 2, characterized in that it is copolymerized with % by weight or less.