JPS6241254A - Flame-retardant resin composition - Google Patents

Abstract

PURPOSE:To provide a flame-retardant resin compsn. having excellent processability, thermally stability, resistance to impact and weather, etc. and suitable for use in the production of automobile parts, by mixing an ABS resin with a vinyl chloride resin having a specified composition. CONSTITUTION:60-90pts.wt. alkyl (meth)acrylate (A) which give a homopolymer having a second-order transition point of -10 deg.C or below (e.g., ethyl acrylate), 39-5pts.wt. monomer (B) which gives a homopolymer having a second-order transition point of 0 deg.C or above (e.g., styrene or acrylonitrile) and 1-30pts.wt. polyfunctional monomer (C) (e.g., ethylene glycol diacrylate) are copolymerized. 99-70pts.wt. vinyl chloride is grafted onto 1-30pts.wt. copolymer. 30-80wt% resulting vinyl chloride resin is mixed with 70-20wt% ABS resin to obtain the desired flame-retardant resin compsn.

Description

[Detailed description of the invention] [Industrial application field] The present invention consists of an ABS resin and a vinyl chloride resin,
This invention relates to a flame-retardant resin composition with excellent processability, impact resistance, and thermal stability.

[Conventional technology]

Conventionally, thermoplastic resins used in fields such as electrical equipment parts, automobile parts, and building materials include high-impact polystyrene resins and acrylonitrile resins, which have excellent impact resistance and rigidity, and extremely good moldability. Rubber-containing #impact polystyrene resins such as butadiene-styrene copolymers (hereinafter referred to as ABS resins) have been widely used.

However, regarding the resins used in this field in recent years,
Increasingly high degree of flame retardancy is required, and there is a desire to develop even more advanced flame retardant resin to replace the polystyrene resin which is flammable to some extent. Things are being proposed.

For example, there are flame-retardant resin compositions containing low-molecular-weight flame retardants represented by phosphorus-containing compounds such as halogenated esters, aromatic halogen-containing compounds, phosphoric esters, and halogenated phosphoric esters.

However, these flame retardants are chemically unstable low-molecular compounds and must be added in a considerable amount to impart a high degree of flame retardancy to the resin. Above all, it may cause a significant decrease in impact strength,
They may impede molding processability by causing coloring due to thermal decomposition during molding, or they may significantly worsen weather resistance.
In many cases, it harms the commercial value of the product.Furthermore, flame retardants are generally expensive, which significantly increases the cost of the product. Resins that can be used for this purpose are difficult to obtain.

On the other hand, focusing on the fact that it is easy to obtain a high degree of balance between flame retardancy and impact strength, recently, flame retardant resins obtained by mixing halogen-containing compounds such as polyvinyl chloride resins and chlorinated polyethylene with other resins have been developed. Many types of resin compositions have been proposed.

For example, a flame-retardant resin composition consisting of a polyvinyl chloride resin and an ABS resin is known (Japanese Patent Publication No. 4B-528).
.

Derived from the properties of the polyvinyl chloride resin, the resin composition certainly has excellent mechanical strength such as impact strength and rigidity, and a resin having a high degree of flame retardancy can be obtained.

Since polyvinyl chloride resin is chemically unstable and prone to thermal decomposition, the resin composition has poor thermal stability, and combined with the poor fluidity of polyvinyl chloride resin, molding processability is poor. has the disadvantage of being significantly reduced.

On the other hand, it is obvious that heat stabilizers such as lead-based compounds and tin-based compounds are added to improve molding processability by increasing the thermal stability of polyvinyl chloride. There are naturally restrictions on the amount of use due to the impact on important fluidity and physical properties and cost.

It is also known to improve the moldability of polyvinyl chloride by reducing the content of molecules with asymmetric structures (branches, double bonds, etc.) in the polymer through ionic polymerization, etc. However, there are industrial problems in terms of polymerization rate and yield. Furthermore, as a method to improve the moldability of resin, there is a method to increase the thermal stability of the resin by increasing the fluidity of the resin and keeping the molding temperature low. decreases, and sufficient effects cannot be obtained.

On the other hand, a flame-retardant resin composition (US Pat. No. 3,494,982) comprising chlorinated polyethylene and ABS resin is also known. Although this composition has better thermal stability than polyvinyl chloride resin compositions, it has the disadvantage of poor moldability due to poor flowability.

As mentioned above, no conventional flame-retardant resin composition has been found that simultaneously satisfies moldability, impact resistance, and weather resistance, which are important for commercial value, and can be put to practical use as a molding material.

[Problem that the invention seeks to solve]

An object of the present invention is to provide a flame-retardant resin composition that has moldability that can be practically used as a molding material, which has been difficult with conventional compositions, and also has impact resistance. .

[Means for solving problems]

As a result of intensive research to achieve the above object, the present inventor found that
The inventors have discovered that a flame-retardant resin composition with excellent processability, impact resistance, and thermal stability can be obtained by combining an ABS resin with a specific vinyl chloride resin, and have thus arrived at the present invention.

That is, the resin composition of the present invention comprises A) 20 to 70% by weight of ABS resin and B) alkyl acrylate and/or alkyl methacrylate whose secondary rearrangement point is -10°C or lower when formed into a homopolymer.
) 1 to 30 parts by weight of a copolymer of 5 to 39 parts by weight of monomers whose secondary rearrangement point is 0°C or more and 1 to 30 parts by weight of a polyfunctional monomer when made into a homopolymer with 80 to 90 parts by weight % by weight of a vinyl chloride resin obtained by graft copolymerizing 70 to 88 parts by weight of vinyl chloride.

This will be explained in detail below.

The content of ABS resin in the flame retardant resin composition of the present invention is 20
-70% by weight, but 30-65% by weight is particularly preferred; if it is less than 20% by weight, processability is poor, and if it exceeds 70% by weight, it is difficult to maintain flame retardancy.

Polybutadiene rubber, which is the polymerization raw material for ABS resin, is
Polybutadiene or 50% by weight or more of butadiene and 50% by weight or less of a heptanoolefin monomer copolymerizable with it, such as aromatic vinyl compounds such as styrene, alkyl acrylates such as methyl acrylate, ethyl acrylate, butyl acrylate; methyl meth It is a copolymer with acrylate, fulkyl methacrylate such as ethyl methacrylate and butyl methacrylate; and a vinyl cyanide compound such as acrylonitrile.

Examples of vinyl cyanide compounds used in ABS resin graft polymerization include acrylonitrile and methacrylonitrile, and examples of aromatic vinyl compounds include styrene, α
- Methyl Φ styrene, chlorostyrene, etc. are typical, and the ratio of use is preferably 10 to 50 parts by weight of vinyl cyanide compound and 20 to 80 parts by weight of aromatic vinyl compound to 10 to 50 parts by weight of the above-mentioned butadiene rubber. .

Further, in addition to the vinyl cyanide compound and the aromatic vinyl compound, a small amount of vinyl monomer copolymerizable with these can be used in the graft polymerization.

All of the above polymerizations can be easily carried out by conventionally known methods such as suspension polymerization and emulsion polymerization, but emulsion polymerization is particularly preferred.

The content of vinyl chloride resin in the flame retardant resin composition of the present invention is 30 to 80% by weight, and preferably 40 to 70% by weight.

If the proportion of the vinyl chloride resin exceeds 80% by weight, it is undesirable because the impact strength and molding processability of the resin composition will decrease.On the other hand, if the proportion is less than 30% by weight, it will be difficult to achieve the objective of the present invention. No flammability is obtained.

In the present invention, the graft polymerization raw material used for the vinyl chloride resin is a copolymer of alkyl acrylate and/or alkyl methacrylate with monomers and polyfunctional monomers (hereinafter referred to as acrylic copolymer) and reinforced vinyl. be.

Alkyl acrylates and alkyl methacrylates are those whose secondary transition point is 110°C or less when made into a homopolymer.1For example, ethyl acrylate, n
-propyl acrylate, iso-butyl acrylate,
n-butyl acrylate, n-hexyl acrylate,
Examples include 2-ethylhexyl acrylate, n-octyl acrylate, n-decyl acrylate, n-octyl methacrylate, n-decyl methacrylate, n-dodecyl methacrylate, and lauryl methacrylate, which contribute to impact resistance.

The alkyl acrylate and/or alkyl methacrylate acts as a soft segment, and the amount used is preferably 80 to 130 parts by weight per 100 parts by weight of the total raw materials used for copolymerization; if it exceeds 90 parts by weight, no improvement in strength can be expected;
If it is less than 0 parts by weight, impact resistance will decrease, which is not preferable.

The monomers of the present invention have a secondary rearrangement point of 0°C or higher when made into a homopolymer, and can be copolymerized to form hard segments (such as styrene, α-
Aromatic vinyls such as methylstyrene and vinyltoluene, and acrylonitrile.

Unsaturated nitriles such as methacrylonitrile, vinyl esters such as vinyl acetate and vinyl propionate, vinyl ethers such as butyl vinyl ether, octyl vinyl ether, and lauryl vinyl ether, alkyl acrylates of methyl acrylate, methyl methacrylate, ethyl methacrylate, propyl methacrylate, etc. Examples include alkyl methacrylates, which can be used alone or in combination of two or more.

The amount of monomers used is preferably 5 to 40 parts by weight,
If it is less than 5 parts by weight, no improvement in strength can be expected, and if it exceeds 40 parts by weight, impact resistance will decrease, which is undesirable.In particular, when an improvement in strength is expected, methyl methacrylate,
Methyl acrylate, acrylonitrile and styrene are preferred.

Polyfunctional monomers include alkyl acrylates and/or
or monomers that cause crosslinking or the like to alkyl methacrylate, such as ethylene glycol diacrylate, diethylene glycol diacrylate, triethylene glycol diacrylate, ethylene glycol dimethacrylate, diethylene glycol dimethacrylate, triethylene glycol dimethacrylate, 1.
3-propylene glycol dimethacrylate, 1.3-
Butylene gelicoldimethacrylate, 1. Examples include acrylates or methacrylates of mono- or polyalkylene gellicols such as tobutylene glycol dimethacrylate, di- or triallyl compounds such as diallyl phthalate, diallyl maleate, diallyl fumarate, diallyl succinate, and divinylbenzene.

The amount of the polyfunctional upper layer used is preferably 1 to 30 parts by weight; if it is less than 1 part by weight, no improvement in strength can be expected, and if it exceeds 30 parts by weight, impact resistance cannot be improved.

The copolymer of alkyl acrylate and/or alkyl methacrylate used in the present invention, monomers, and polyfunctional monomers can be prepared using a commonly known emulsifier 1 by polymerization methods such as emulsion polymerization, suspension polymerization, solution polymerization, or bulk polymerization. Although it can be obtained using a dispersant, a catalyst, etc., it is preferable to employ emulsion polymerization.

The amount of the acrylic copolymer used as the backbone polymer in the graft copolymerization to obtain the vinyl chloride resin component of the present invention is 100 parts by weight in total including the amount of vinyl chloride used as another raw material for the graft copolymerization. A suitable amount is 1 to 30 parts by weight. If the amount of the acrylic copolymer used is less than 1 part by weight, the impact resistance will not be sufficient, and if it exceeds 30 parts by weight, the impact resistance will improve but the strength will decrease, which is not preferred.

The graft copolymerization method of the present invention includes an aqueous suspension polymerization method,
Examples include aqueous emulsion polymerization, solution polymerization, and solutionless polymerization, but aqueous suspension polymerization is preferred.When performing aqueous suspension polymerization, the sum of the acrylic copolymer as the backbone polymer and the vinyl chloride monomer is used. and water in a weight ratio of 1:1 to 1:5, preferably 1:1 to 1:3. A method for obtaining a graft copolymerized vinyl chloride resin by a general suspension polymerization method is, for example, to add pure water, a suspension stabilizer such as hydroxypropyl methylcellulose, a radical polymerization initiator, and the necessary materials into a jacketed polymerization reactor. Accordingly, a degree of polymerization reducing agent is added, the acrylic copolymer is added thereto and suspended, the air inside the can is then removed, and then vinyl chloride is charged together with other vinyl compounds as required. Thereafter, the inside of the can is heated by a jacket, the acrylic copolymer is dissolved in vinyl chloride, and graft copolymerization is started. Graft copolymerization is an exothermic reaction, and the internal temperature is controlled by a jacket if necessary.After the reaction is completed, unreacted vinyl chloride is removed from the outside of the can to obtain a slurry of graft copolymer resin.

The slurry is then dehydrated and dry bombed in a conventional manner to obtain a graft copolymerized vinyl chloride resin. The charging method to the polymerization reactor is not limited, and among the charged raw materials such as pure water, suspension stabilizer, acrylic copolymer, and vinyl chloride, the acrylic copolymer may be dissolved in vinyl chloride. A method is also adopted in which the material is then charged.

In graft copolymerization, other monomers may be present in the coexistence within a range that does not reduce the impact resistance, weather resistance, and flexural modulus.

The resin composition of the present invention may optionally contain various additives such as other flame retardants, ultraviolet absorbers, antioxidants, colorants, lubricants, and heat stabilizers.

The resin composition of the present invention can be used in mixing rolls, co-kneaders,
It can be easily melt-mixed using a mixer such as a Banbury Mixer 1 extruder.

The thus obtained resin composition of the present invention can be widely used in fields such as electrical parts, automobile parts, building materials, office machine parts, etc., which require a high degree of flame retardancy.

The present invention will be explained in detail below using Examples and Reference Examples.

In addition, each physical property value in this invention was measured by the following method.

(1) Measurement of moldability (fluidity) Take 1g of extruded pellets, inner diameter 1++++s, length 10m.
- using a die, pressure 150 kg/cm', temperature 2
The flow rate was measured using a Koka type flow tester under the condition of 00°C.

(2) Measurement of moldability (thermal stability) (2)-1CR thermal stability test (static thermal stability) JIS
The time (minutes) until the start of decomposition was measured according to the K-8723 method. However, the temperature was 200°C.

(2)-2 Dynamic thermal stability extrusion pellets) 32g was charged into a rotor mixer with an internal volume of 30cc and a batch type plastograph at a temperature of 180°C.
The mixture was kneaded at a rotational speed of 5 Or, p, +s, and a load of 10.0 kg, and the time (minutes) until the torque started to increase again after it decreased and entered a steady state was measured.

(3) Measurement of impact strength Izot impact test obtained by molding with a 402 injection molding machine at injection molding temperatures of 180°, 200', 200°C and a molding cycle of 1 minute according to ASTM-258 method. Izot impact strength was measured using the piece. However, a mold with a notch was used.

(4) Flame retardant υL-34 method: Sample thickness 1/8 inch test piece used.

〔Example〕

Examples 1-6. Reference Examples 1 to 11 (1) Production of ABS resin Based on the amounts of raw materials used shown in Table 1, emulsion polymerization was carried out at 80°C to obtain Polymer (A)-1-10. The composition of the solid polybutadiene latex used is as follows.

PB-1...Butadiene content 100% (wt%,
Same hereafter) PB-2...Butadiene content 60%, styrene content 40%PB-3...Butadiene content 60%, acrylonitrile content 40% PR-4...Butadiene content 40%, styrene content: 40%, acrylonitrile content: 20% The amounts of each raw material used in Table 1 are parts by weight (the same applies to Tables 2 and below).

(2) Production of vinyl chloride resin Based on the amounts of raw materials used shown in Table 2, aqueous suspension polymerization was carried out at 63° C. to obtain polymers (B)-1 to 10.

The temperature of the secondary transition point of acrylic resin homopolymer is as follows.

Poly-n-butyl acrylate ・・・・・・-5
6°C poly-2-ethylhexyl acrylate...
・・・-20℃ Methyl acrylate ・・・・・・ 0℃
Methyl methacrylate - 45°C (3) Production of the resin composition of the present invention The ABS resin obtained in the above (1) and the vinyl chloride resin obtained in the above (2) are In addition, 2.5 parts by weight of dibutyltin mercaptide as a stabilizer was mixed at 90°C for 10 minutes at 90°C for 10 minutes as a stabilizer in the proportions shown in Tables and Table 4.
The mixture was melted and kneaded at 200°C using an extruder to form pellets.

Next, test pieces for measuring physical properties were prepared using a 4-ounce injection molding machine. In this case, the molding temperature is 1 at the cylinder temperature.
The temperature was 80.200.200°C. The various physical property tests described above were conducted using the pellet and test piece thus obtained.

The evaluation results are shown in Table 3.4 along with reference examples.

As is clear from Table 3.4, the composition of the present invention is excellent in terms of processability, physical strength, and flame retardancy.

〔Effect of the invention〕

As described in detail above, the present invention provides a flame-retardant resin composition with excellent processability, impact resistance, and thermal stability, and greatly contributes to improving the quality and expanding the use of flame-retardant resins. big.

Claims (1)

[Claims] A) 20 to 70% by weight of ABS resin and B) when made into a homopolymer, the secondary dislocation point is -10
5 to 3 monomers whose secondary rearrangement point is 0°C or higher when formed into a homopolymer with 60 to 90 parts by weight of alkyl acrylate and/or alkyl methacrylate having a temperature of 0°C or lower
Vinyl chloride resin 30 to 80% obtained by graft copolymerizing 70 to 99 parts by weight of vinyl chloride to 1 to 30 parts by weight of a copolymer of 9 parts by weight and 1 to 30 parts by weight of a polyfunctional monomer.
A flame retardant resin composition consisting of % by weight.